diff --git a/app/assets/javascripts/discourse/app/components/sidebar/user/sections.hbs b/app/assets/javascripts/discourse/app/components/sidebar/user/sections.hbs
index 47044fd4e95..a5987ba0d94 100644
--- a/app/assets/javascripts/discourse/app/components/sidebar/user/sections.hbs
+++ b/app/assets/javascripts/discourse/app/components/sidebar/user/sections.hbs
@@ -6,7 +6,7 @@
     <Sidebar::User::TagsSection @collapsable={{@collapsableSections}}/>
   {{/if}}
 
-  {{#if this.siteSettings.enable_personal_messages}}
+  {{#if this.enableMessagesSection}}
     <Sidebar::User::MessagesSection @collapsable={{@collapsableSections}}/>
   {{/if}}
 
diff --git a/app/assets/javascripts/discourse/app/components/sidebar/user/sections.js b/app/assets/javascripts/discourse/app/components/sidebar/user/sections.js
index 36428e17a8b..41ed90a1b26 100644
--- a/app/assets/javascripts/discourse/app/components/sidebar/user/sections.js
+++ b/app/assets/javascripts/discourse/app/components/sidebar/user/sections.js
@@ -6,6 +6,7 @@ import { inject as service } from "@ember/service";
 export default class SidebarUserSections extends Component {
   @service siteSettings;
   @service currentUser;
+  @service site;
 
   customSections;
 
@@ -21,4 +22,8 @@ export default class SidebarUserSections extends Component {
       return section;
     });
   }
+
+  get enableMessagesSection() {
+    return this.currentUser?.allowPersonalMessages;
+  }
 }
diff --git a/app/assets/javascripts/discourse/app/components/topic-footer-buttons.js b/app/assets/javascripts/discourse/app/components/topic-footer-buttons.js
index ab1430ae508..e352343170b 100644
--- a/app/assets/javascripts/discourse/app/components/topic-footer-buttons.js
+++ b/app/assets/javascripts/discourse/app/components/topic-footer-buttons.js
@@ -15,9 +15,9 @@ export default Component.extend({
   // Allow us to extend it
   layoutName: "components/topic-footer-buttons",
 
-  @discourseComputed("topic.isPrivateMessage")
-  canArchive(isPM) {
-    return this.siteSettings.enable_personal_messages && isPM;
+  @discourseComputed("canSendPms", "topic.isPrivateMessage")
+  canArchive(canSendPms, isPM) {
+    return canSendPms && isPM;
   },
 
   inlineButtons: getTopicFooterButtons(),
@@ -43,7 +43,12 @@ export default Component.extend({
 
   @discourseComputed("topic.isPrivateMessage")
   showNotificationsButton(isPM) {
-    return !isPM || this.siteSettings.enable_personal_messages;
+    return !isPM || this.canSendPms;
+  },
+
+  @discourseComputed("currentUser.allowPersonalMessages")
+  canSendPms() {
+    return this.currentUser?.allowPersonalMessages;
   },
 
   canInviteTo: alias("topic.details.can_invite_to"),
diff --git a/app/assets/javascripts/discourse/app/components/user-menu/menu.js b/app/assets/javascripts/discourse/app/components/user-menu/menu.js
index 501ebaa871e..fc9688a2e1f 100644
--- a/app/assets/javascripts/discourse/app/components/user-menu/menu.js
+++ b/app/assets/javascripts/discourse/app/components/user-menu/menu.js
@@ -163,9 +163,7 @@ const CORE_TOP_TABS = [
     }
 
     get shouldDisplay() {
-      return (
-        this.siteSettings.enable_personal_messages || this.currentUser.staff
-      );
+      return this.currentUser?.allowPersonalMessages;
     }
 
     get notificationTypes() {
diff --git a/app/assets/javascripts/discourse/app/controllers/group.js b/app/assets/javascripts/discourse/app/controllers/group.js
index 27f074fd93e..a847b619c20 100644
--- a/app/assets/javascripts/discourse/app/controllers/group.js
+++ b/app/assets/javascripts/discourse/app/controllers/group.js
@@ -88,9 +88,13 @@ export default Controller.extend({
     return defaultTabs;
   },
 
-  @discourseComputed("model.has_messages", "model.is_group_user")
+  @discourseComputed(
+    "model.has_messages",
+    "model.is_group_user",
+    "currentUser.allowPersonalMessages"
+  )
   showMessages(hasMessages, isGroupUser) {
-    if (!this.siteSettings.enable_personal_messages) {
+    if (!this.currentUser?.allowPersonalMessages) {
       return false;
     }
 
diff --git a/app/assets/javascripts/discourse/app/controllers/keyboard-shortcuts-help.js b/app/assets/javascripts/discourse/app/controllers/keyboard-shortcuts-help.js
index a1bcbfa432b..efc7ed5e9f4 100644
--- a/app/assets/javascripts/discourse/app/controllers/keyboard-shortcuts-help.js
+++ b/app/assets/javascripts/discourse/app/controllers/keyboard-shortcuts-help.js
@@ -326,7 +326,7 @@ export default Controller.extend(ModalFunctionality, {
       bookmarks: buildShortcut("jump_to.bookmarks", { keys1: ["g", "b"] }),
       profile: buildShortcut("jump_to.profile", { keys1: ["g", "p"] }),
     };
-    if (this.siteSettings.enable_personal_messages) {
+    if (this.currentUser?.allowPersonalMessages) {
       shortcuts.messages = buildShortcut("jump_to.messages", {
         keys1: ["g", "m"],
       });
diff --git a/app/assets/javascripts/discourse/app/controllers/preferences/notifications.js b/app/assets/javascripts/discourse/app/controllers/preferences/notifications.js
index 55b6304d354..897c9fb30a6 100644
--- a/app/assets/javascripts/discourse/app/controllers/preferences/notifications.js
+++ b/app/assets/javascripts/discourse/app/controllers/preferences/notifications.js
@@ -1,4 +1,5 @@
 import Controller from "@ember/controller";
+import discourseComputed from "discourse-common/utils/decorators";
 import I18n from "I18n";
 import { NotificationLevels } from "discourse/lib/notification-levels";
 import { popupAjaxError } from "discourse/lib/ajax-error";
@@ -89,6 +90,11 @@ export default Controller.extend({
     ];
   },
 
+  @discourseComputed("currentUser.allowPersonalMessages")
+  showMessageSettings() {
+    return this.currentUser?.allowPersonalMessages;
+  },
+
   actions: {
     save() {
       this.set("saved", false);
diff --git a/app/assets/javascripts/discourse/app/controllers/preferences/users.js b/app/assets/javascripts/discourse/app/controllers/preferences/users.js
index 65f457bbfdc..f20db86e7ba 100644
--- a/app/assets/javascripts/discourse/app/controllers/preferences/users.js
+++ b/app/assets/javascripts/discourse/app/controllers/preferences/users.js
@@ -72,6 +72,11 @@ export default Controller.extend({
     return !allowPrivateMessages;
   },
 
+  @discourseComputed("currentUser.allowPersonalMessages")
+  showMessageSettings() {
+    return this.currentUser?.allowPersonalMessages;
+  },
+
   @action
   save() {
     this.set("saved", false);
diff --git a/app/assets/javascripts/discourse/app/controllers/topic.js b/app/assets/javascripts/discourse/app/controllers/topic.js
index d6604556f0b..aace5530cbe 100644
--- a/app/assets/javascripts/discourse/app/controllers/topic.js
+++ b/app/assets/javascripts/discourse/app/controllers/topic.js
@@ -212,6 +212,11 @@ export default Controller.extend(bufferedProperty("model"), {
     );
   },
 
+  @discourseComputed("currentUser.allowPersonalMessages")
+  canSendPms() {
+    return this.currentUser?.allowPersonalMessages;
+  },
+
   @discourseComputed("buffered.category_id")
   minimumRequiredTags(categoryId) {
     return Category.findById(categoryId)?.minimumRequiredTags || 0;
diff --git a/app/assets/javascripts/discourse/app/controllers/user.js b/app/assets/javascripts/discourse/app/controllers/user.js
index 1c00e2fd7c3..4c8ba40cbca 100644
--- a/app/assets/javascripts/discourse/app/controllers/user.js
+++ b/app/assets/javascripts/discourse/app/controllers/user.js
@@ -116,11 +116,13 @@ export default Controller.extend(CanCheckEmails, {
     return viewingSelf;
   },
 
-  @discourseComputed("viewingSelf", "currentUser.admin")
+  @discourseComputed(
+    "viewingSelf",
+    "currentUser.admin",
+    "currentUser.allowPersonalMessages"
+  )
   showPrivateMessages(viewingSelf, isAdmin) {
-    return (
-      this.siteSettings.enable_personal_messages && (viewingSelf || isAdmin)
-    );
+    return this.currentUser?.allowPersonalMessages && (viewingSelf || isAdmin);
   },
 
   @discourseComputed("viewingSelf", "currentUser.admin")
diff --git a/app/assets/javascripts/discourse/app/lib/keyboard-shortcuts.js b/app/assets/javascripts/discourse/app/lib/keyboard-shortcuts.js
index 8de8bca0062..f6b8d156eff 100644
--- a/app/assets/javascripts/discourse/app/lib/keyboard-shortcuts.js
+++ b/app/assets/javascripts/discourse/app/lib/keyboard-shortcuts.js
@@ -137,9 +137,10 @@ export default {
     this.appEvents = this.container.lookup("service:app-events");
     this.currentUser = this.container.lookup("service:current-user");
     this.siteSettings = this.container.lookup("service:site-settings");
+    this.site = this.container.lookup("service:site");
 
     // Disable the shortcut if private messages are disabled
-    if (!this.siteSettings.enable_personal_messages) {
+    if (!this.currentUser?.allowPersonalMessages) {
       delete DEFAULT_BINDINGS["g m"];
     }
   },
diff --git a/app/assets/javascripts/discourse/app/models/user.js b/app/assets/javascripts/discourse/app/models/user.js
index 3e11d6ef094..5b833911933 100644
--- a/app/assets/javascripts/discourse/app/models/user.js
+++ b/app/assets/javascripts/discourse/app/models/user.js
@@ -626,6 +626,18 @@ const User = RestModel.extend({
     return filteredGroups.length > numGroupsToDisplay;
   },
 
+  isInAnyGroups(groupIds) {
+    if (!this.groups) {
+      return;
+    }
+
+    // auto group ID 0 is "everyone"
+    return (
+      groupIds.includes(0) ||
+      this.groups.mapBy("id").some((groupId) => groupIds.includes(groupId))
+    );
+  },
+
   // The user's stat count, excluding PMs.
   @discourseComputed("statsExcludingPms.@each.count")
   statsCountNonPM() {
@@ -1062,6 +1074,18 @@ const User = RestModel.extend({
   trackedTags(trackedTags, watchedTags, watchingFirstPostTags) {
     return [...trackedTags, ...watchedTags, ...watchingFirstPostTags];
   },
+
+  @discourseComputed("staff", "groups.[]")
+  allowPersonalMessages() {
+    return (
+      this.staff ||
+      this.isInAnyGroups(
+        this.siteSettings.personal_message_enabled_groups
+          .split("|")
+          .map((groupId) => parseInt(groupId, 10))
+      )
+    );
+  },
 });
 
 User.reopenClass(Singleton, {
diff --git a/app/assets/javascripts/discourse/app/templates/preferences/notifications.hbs b/app/assets/javascripts/discourse/app/templates/preferences/notifications.hbs
index 3d1f882f904..6f142e25a1c 100644
--- a/app/assets/javascripts/discourse/app/templates/preferences/notifications.hbs
+++ b/app/assets/javascripts/discourse/app/templates/preferences/notifications.hbs
@@ -33,7 +33,7 @@
 
 <UserNotificationSchedule @model={{this.model}} />
 
-{{#if this.siteSettings.enable_personal_messages}}
+{{#if this.showMessageSettings}}
   <div class="control-group private-messages">
     <label class="control-label">{{i18n "user.private_messages"}}</label>
 
diff --git a/app/assets/javascripts/discourse/app/templates/preferences/users.hbs b/app/assets/javascripts/discourse/app/templates/preferences/users.hbs
index ebf6b46a744..5589f14d47e 100644
--- a/app/assets/javascripts/discourse/app/templates/preferences/users.hbs
+++ b/app/assets/javascripts/discourse/app/templates/preferences/users.hbs
@@ -21,7 +21,7 @@
   <div class="instructions">{{i18n "user.muted_users_instructions"}}</div>
 </div>
 
-{{#if this.siteSettings.enable_personal_messages}}
+{{#if this.showMessageSettings}}
   <div class="control-group user-allow-pm">
     <div class="controls">
       <PreferenceCheckbox @labelKey="user.allow_private_messages_from_specific_users" @checked={{this.model.user_option.enable_allowed_pm_users}} @disabled={{this.disableAllowPmUsersSetting}} />
diff --git a/app/assets/javascripts/discourse/app/templates/topic.hbs b/app/assets/javascripts/discourse/app/templates/topic.hbs
index 3d49a7357c6..41fa19fd1d5 100644
--- a/app/assets/javascripts/discourse/app/templates/topic.hbs
+++ b/app/assets/javascripts/discourse/app/templates/topic.hbs
@@ -52,7 +52,7 @@
         {{else}}
           <h1 data-topic-id={{this.model.id}}>
             {{#unless this.model.is_warning}}
-              {{#if this.siteSettings.enable_personal_messages}}
+              {{#if this.canSendPms}}
                 <PrivateMessageGlyph @shouldShow={{this.model.isPrivateMessage}} @href={{this.pmPath}} @title="topic_statuses.personal_message.title" @ariaLabel="user.messages.inbox" @tagName="" />
               {{else}}
                 <PrivateMessageGlyph @shouldShow={{this.model.isPrivateMessage}} @tagName="" />
diff --git a/app/assets/javascripts/discourse/app/widgets/user-menu.js b/app/assets/javascripts/discourse/app/widgets/user-menu.js
index 3e4efc53b6e..49e589e7679 100644
--- a/app/assets/javascripts/discourse/app/widgets/user-menu.js
+++ b/app/assets/javascripts/discourse/app/widgets/user-menu.js
@@ -156,7 +156,7 @@ createWidget("user-menu-links", {
 
     glyphs.push(this.bookmarksGlyph());
 
-    if (this.siteSettings.enable_personal_messages || this.currentUser.staff) {
+    if (this.currentUser?.allowPersonalMessages) {
       glyphs.push(this.messagesGlyph());
     }
 
diff --git a/app/assets/javascripts/discourse/tests/acceptance/sidebar-user-messages-section-test.js b/app/assets/javascripts/discourse/tests/acceptance/sidebar-user-messages-section-test.js
index ad18f04e126..c42ba0d83e2 100644
--- a/app/assets/javascripts/discourse/tests/acceptance/sidebar-user-messages-section-test.js
+++ b/app/assets/javascripts/discourse/tests/acceptance/sidebar-user-messages-section-test.js
@@ -12,14 +12,14 @@ import {
 import { NotificationLevels } from "discourse/lib/notification-levels";
 
 acceptance(
-  "Sidebar - Logged on user - Messages Section - enable_personal_messages disabled",
+  "Sidebar - Logged on user - Messages Section - user not in personal_message_enabled_groups",
   function (needs) {
-    needs.user();
+    needs.user({ moderator: false, admin: false });
 
     needs.settings({
       enable_experimental_sidebar_hamburger: true,
       enable_sidebar: true,
-      enable_personal_messages: false,
+      personal_message_enabled_groups: "13", // trust_level_3 auto group ID;
     });
 
     test("clicking on section header button", async function (assert) {
@@ -34,7 +34,7 @@ acceptance(
 );
 
 acceptance(
-  "Sidebar - Logged on user - Messages Section - enable_personal_messages enabled",
+  "Sidebar - Logged on user - Messages Section - user in personal_message_enabled_groups",
   function (needs) {
     needs.user();
 
diff --git a/app/assets/javascripts/discourse/tests/fixtures/session-fixtures.js b/app/assets/javascripts/discourse/tests/fixtures/session-fixtures.js
index 08a365ecaab..d99b6ab8258 100644
--- a/app/assets/javascripts/discourse/tests/fixtures/session-fixtures.js
+++ b/app/assets/javascripts/discourse/tests/fixtures/session-fixtures.js
@@ -33,7 +33,21 @@ export default {
       timezone: "Australia/Brisbane",
       skip_new_user_tips: false,
       can_review: true,
-      ignored_users: []
+      ignored_users: [],
+      groups: [
+        {
+          id: 10,
+          automatic: true,
+          name: "trust_level_0",
+          display_name: "trust_level_0",
+        },
+        {
+          id: 11,
+          automatic: true,
+          name: "trust_level_1",
+          display_name: "trust_level_1",
+        }
+      ]
     },
   },
 };
diff --git a/app/assets/javascripts/discourse/tests/helpers/component-test.js b/app/assets/javascripts/discourse/tests/helpers/component-test.js
index ed8cfde25d2..4e79dd558a1 100644
--- a/app/assets/javascripts/discourse/tests/helpers/component-test.js
+++ b/app/assets/javascripts/discourse/tests/helpers/component-test.js
@@ -25,6 +25,23 @@ export function setupRenderingTest(hooks) {
     const currentUser = User.create({
       username: "eviltrout",
       timezone: "Australia/Brisbane",
+      name: "Robin Ward",
+      admin: false,
+      moderator: false,
+      groups: [
+        {
+          id: 10,
+          automatic: true,
+          name: "trust_level_0",
+          display_name: "trust_level_0",
+        },
+        {
+          id: 11,
+          automatic: true,
+          name: "trust_level_1",
+          display_name: "trust_level_1",
+        },
+      ],
     });
     this.currentUser = currentUser;
     this.owner.unregister("service:current-user");
diff --git a/app/assets/javascripts/discourse/tests/helpers/site-settings.js b/app/assets/javascripts/discourse/tests/helpers/site-settings.js
index 95c591654ab..4f02fb7839a 100644
--- a/app/assets/javascripts/discourse/tests/helpers/site-settings.js
+++ b/app/assets/javascripts/discourse/tests/helpers/site-settings.js
@@ -95,6 +95,7 @@ const ORIGINAL_SETTINGS = {
   desktop_category_page_style: "categories_and_latest_topics",
   enable_mentions: true,
   enable_personal_messages: true,
+  personal_message_enabled_groups: "11", // TL1 group
   unicode_usernames: false,
   secure_media: false,
   external_emoji_url: "",
diff --git a/app/assets/javascripts/discourse/tests/integration/components/user-menu/menu-test.js b/app/assets/javascripts/discourse/tests/integration/components/user-menu/menu-test.js
index a0de1cada5e..e4e131b88eb 100644
--- a/app/assets/javascripts/discourse/tests/integration/components/user-menu/menu-test.js
+++ b/app/assets/javascripts/discourse/tests/integration/components/user-menu/menu-test.js
@@ -98,10 +98,11 @@ module("Integration | Component | user-menu", function (hooks) {
     );
   });
 
-  test("messages tab isn't shown if current user isn't staff and enable_personal_messages setting is disabled", async function (assert) {
+  test("messages tab isn't shown if current user isn't staff and user does not belong to personal_message_enabled_groups", async function (assert) {
     this.currentUser.set("moderator", false);
     this.currentUser.set("admin", false);
-    this.siteSettings.enable_personal_messages = false;
+    this.currentUser.set("groups", []);
+    this.siteSettings.personal_message_enabled_groups = "13"; // trust_level_3 auto group ID;
 
     await render(template);
 
@@ -117,10 +118,11 @@ module("Integration | Component | user-menu", function (hooks) {
     );
   });
 
-  test("messages tab is shown if current user is staff even if enable_personal_messages setting is disabled", async function (assert) {
+  test("messages tab is shown if current user is staff even if they do not belong to personal_message_enabled_groups", async function (assert) {
     this.currentUser.set("moderator", true);
     this.currentUser.set("admin", false);
-    this.siteSettings.enable_personal_messages = false;
+    this.currentUser.set("groups", []);
+    this.siteSettings.personal_message_enabled_groups = "999";
 
     await render(template);
 
diff --git a/app/assets/javascripts/discourse/tests/integration/components/widgets/hamburger-menu-test.js b/app/assets/javascripts/discourse/tests/integration/components/widgets/hamburger-menu-test.js
index f0913a66780..23b4a074dbe 100644
--- a/app/assets/javascripts/discourse/tests/integration/components/widgets/hamburger-menu-test.js
+++ b/app/assets/javascripts/discourse/tests/integration/components/widgets/hamburger-menu-test.js
@@ -34,7 +34,7 @@ module("Integration | Component | Widget | hamburger-menu", function (hooks) {
   });
 
   test("staff menu - not staff", async function (assert) {
-    this.currentUser.set("staff", false);
+    this.currentUser.setProperties({ admin: false, moderator: false });
 
     await render(hbs`<MountWidget @widget="hamburger-menu" />`);
 
diff --git a/app/assets/javascripts/discourse/tests/integration/components/widgets/user-menu-test.js b/app/assets/javascripts/discourse/tests/integration/components/widgets/user-menu-test.js
index 3989fd854eb..a3e717edc90 100644
--- a/app/assets/javascripts/discourse/tests/integration/components/widgets/user-menu-test.js
+++ b/app/assets/javascripts/discourse/tests/integration/components/widgets/user-menu-test.js
@@ -92,7 +92,8 @@ module("Integration | Component | Widget | user-menu", function (hooks) {
   });
 
   test("private messages - disabled", async function (assert) {
-    this.siteSettings.enable_personal_messages = false;
+    this.currentUser.setProperties({ admin: false, moderator: false });
+    this.siteSettings.personal_message_enabled_groups = "13"; // trust_level_3 auto group ID;
 
     await render(hbs`<MountWidget @widget="user-menu" />`);
 
@@ -100,7 +101,7 @@ module("Integration | Component | Widget | user-menu", function (hooks) {
   });
 
   test("private messages - enabled", async function (assert) {
-    this.siteSettings.enable_personal_messages = true;
+    this.siteSettings.personal_message_enabled_groups = "11"; // trust_level_1 auto group ID;
 
     await render(hbs`<MountWidget @widget="user-menu" />`);
 
diff --git a/app/controllers/users_controller.rb b/app/controllers/users_controller.rb
index 662a2c3a6e9..9367dd73ffa 100644
--- a/app/controllers/users_controller.rb
+++ b/app/controllers/users_controller.rb
@@ -1799,7 +1799,7 @@ class UsersController < ApplicationController
       raise Discourse::InvalidAccess.new("username doesn't match current_user's username")
     end
 
-    if !current_user.staff? && !SiteSetting.enable_personal_messages
+    if !current_user.staff? && !current_user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map)
       raise Discourse::InvalidAccess.new("personal messages are disabled.")
     end
 
diff --git a/app/models/site_setting.rb b/app/models/site_setting.rb
index b074d95af44..fc73aa76dc6 100644
--- a/app/models/site_setting.rb
+++ b/app/models/site_setting.rb
@@ -193,6 +193,7 @@ class SiteSetting < ActiveRecord::Base
 
   def self.whispers_allowed_group_ids
     if SiteSetting.enable_whispers && SiteSetting.whispers_allowed_groups.present?
+      # TODO (martin) Change to whispers_allowed_groups_map
       SiteSetting.whispers_allowed_groups.split("|").map(&:to_i)
     else
       []
diff --git a/app/models/user.rb b/app/models/user.rb
index 24afd78f3ca..0fbc35849e3 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -412,6 +412,14 @@ class User < ActiveRecord::Base
     find_by(username_lower: normalize_username(username))
   end
 
+  def in_any_groups?(group_ids)
+    group_ids.include?(Group::AUTO_GROUPS[:everyone]) || (group_ids & belonging_to_group_ids).any?
+  end
+
+  def belonging_to_group_ids
+    @belonging_to_group_ids ||= group_users.pluck(:group_id)
+  end
+
   def group_granted_trust_level
     GroupUser
       .where(user_id: id)
@@ -495,6 +503,7 @@ class User < ActiveRecord::Base
     @user_fields_cache = nil
     @ignored_user_ids = nil
     @muted_user_ids = nil
+    @belonging_to_group_ids = nil
     super
   end
 
@@ -1462,6 +1471,8 @@ class User < ActiveRecord::Base
         GroupActionLogger.new(Discourse.system_user, group).log_add_user_to_group(self)
       end
     end
+
+    @belonging_to_group_ids = nil
   end
 
   def email
diff --git a/app/serializers/current_user_serializer.rb b/app/serializers/current_user_serializer.rb
index ead635ea801..17d468d0b27 100644
--- a/app/serializers/current_user_serializer.rb
+++ b/app/serializers/current_user_serializer.rb
@@ -347,7 +347,7 @@ class CurrentUserSerializer < BasicUserSerializer
 
   def redesigned_user_page_nav_enabled
     if SiteSetting.enable_new_user_profile_nav_groups.present?
-      GroupUser.exists?(user_id: object.id, group_id: SiteSetting.enable_new_user_profile_nav_groups.split("|"))
+      object.in_any_groups?(SiteSetting.enable_new_user_profile_nav_groups_map)
     else
       false
     end
diff --git a/config/locales/server.en.yml b/config/locales/server.en.yml
index ed274972cbd..50e57853af0 100644
--- a/config/locales/server.en.yml
+++ b/config/locales/server.en.yml
@@ -1566,7 +1566,8 @@ en:
     summary_max_results: "Maximum posts returned by 'Summarize This Topic'"
     summary_timeline_button: "Show a 'Summarize' button in the timeline"
 
-    enable_personal_messages: "Allow trust level 1 (configurable via min trust to send messages) users to create messages and reply to messages. Note that staff can always send messages no matter what."
+    enable_personal_messages: "DEPRECATED, use the 'personal message enabled groups' setting instead. Allow trust level 1 (configurable via min trust to send messages) users to create messages and reply to messages. Note that staff can always send messages no matter what."
+    personal_message_enabled_groups: "Allow users within these groups to create messages and reply to messages. Trust level groups include all trust levels above that number, for example choosing trust_level_1 also allows trust_level_2, 3, 4 users to send PMs. Note that staff can always send messages no matter what."
     enable_system_message_replies: "Allows users to reply to system messages, even if personal messages are disabled"
     enable_chunked_encoding: "Enable chunked encoding responses by the server. This feature works on most setups however some proxies may buffer, causing responses to be delayed"
     long_polling_base_url: "Base URL used for long polling (when a CDN is serving dynamic content, be sure to set this to origin pull) eg: http://origin.site.com"
@@ -1889,7 +1890,7 @@ en:
 
     min_trust_to_allow_self_wiki: "The minimum trust level required to make user's own post wiki."
 
-    min_trust_to_send_messages: "The minimum trust level required to create new personal messages."
+    min_trust_to_send_messages: "DEPRECATED, use the 'personal message enabled groups' setting instead. The minimum trust level required to create new personal messages."
     min_trust_to_send_email_messages: "The minimum trust level required to send personal messages via email."
     min_trust_to_flag_posts: "The minimum trust level required to flag posts"
     min_trust_to_post_links: "The minimum trust level required to include links in posts"
@@ -2388,6 +2389,7 @@ en:
       reply_by_email_address_is_empty: "You must set a 'reply by email address' before enabling reply by email."
       email_polling_disabled: "You must enable either manual or POP3 polling before enabling reply by email."
       user_locale_not_enabled: "You must first enable 'allow user locale' before enabling this setting."
+      personal_message_enabled_groups_invalid: "You must specify at least one group for this setting. If you do not want anyone except staff to send PMs, choose the staff group."
       invalid_regex: "Regex is invalid or not allowed."
       invalid_regex_with_message: "The regex '%{regex}' has an error: %{message}"
       email_editable_enabled: "You must disable 'email editable' before enabling this setting."
diff --git a/config/site_settings.yml b/config/site_settings.yml
index 5c83f6af3fc..c447cff5537 100644
--- a/config/site_settings.yml
+++ b/config/site_settings.yml
@@ -818,6 +818,13 @@ posting:
     client: true
   enable_system_message_replies:
     default: true
+  personal_message_enabled_groups:
+    default: "11" # auto group trust_level_1
+    type: group_list
+    client: true
+    allow_any: false
+    refresh: true
+    validator: "PersonalMessageEnabledGroupsValidator"
   editing_grace_period: 300
   editing_grace_period_max_diff: 100
   editing_grace_period_max_diff_high_trust: 400
diff --git a/db/migrate/20220825054405_fill_personal_message_enabled_groups_based_on_deprecated_settings.rb b/db/migrate/20220825054405_fill_personal_message_enabled_groups_based_on_deprecated_settings.rb
new file mode 100644
index 00000000000..cc10befd0f7
--- /dev/null
+++ b/db/migrate/20220825054405_fill_personal_message_enabled_groups_based_on_deprecated_settings.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+class FillPersonalMessageEnabledGroupsBasedOnDeprecatedSettings < ActiveRecord::Migration[7.0]
+  def up
+    enable_personal_messages_raw = DB.query_single("SELECT value FROM site_settings WHERE name = 'enable_personal_messages'").first
+    enable_personal_messages = enable_personal_messages_raw.blank? || enable_personal_messages_raw == 't'
+
+    min_trust_to_send_messages_raw = DB.query_single("SELECT value FROM site_settings WHERE name = 'min_trust_to_send_messages'").first
+    min_trust_to_send_messages = (min_trust_to_send_messages_raw.blank? ? 1 : min_trust_to_send_messages_raw).to_i
+
+    # default to TL1, Group::AUTO_GROUPS[:trust_level_1] is 11
+    personal_message_enabled_groups = "11"
+
+    if min_trust_to_send_messages != 1
+      # Group::AUTO_GROUPS[:trust_level_N] range from 10-14
+      personal_message_enabled_groups = "1#{min_trust_to_send_messages}"
+    end
+
+    # only allow staff if the setting was previously disabled, Group::AUTO_GROUPS[:staff] is 3
+    if !enable_personal_messages
+      personal_message_enabled_groups = "3"
+    end
+
+    # data_type 20 is group_list
+    DB.exec(
+      "INSERT INTO site_settings(name, value, data_type, created_at, updated_at)
+      VALUES('personal_message_enabled_groups', :setting, '20', NOW(), NOW())",
+      setting: personal_message_enabled_groups
+    )
+  end
+
+  def down
+    raise ActiveRecord::IrreversibleMigration
+  end
+end
diff --git a/lib/guardian.rb b/lib/guardian.rb
index a0f98dab147..d4b557ec4ac 100644
--- a/lib/guardian.rb
+++ b/lib/guardian.rb
@@ -71,6 +71,9 @@ class Guardian
     def whisperer?
       false
     end
+    def in_any_groups?(group_ids)
+      false
+    end
   end
 
   attr_reader :request
@@ -398,7 +401,12 @@ class Guardian
     if object.is_a?(Topic)
       if object.private_message?
         return true if is_admin?
-        return false unless SiteSetting.enable_personal_messages?
+
+        # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+        if !@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map) ||
+            !SiteSetting.enable_personal_messages
+          return false
+        end
         return false if object.reached_recipients_limit? && !is_staff?
       end
 
@@ -447,12 +455,11 @@ class Guardian
     (is_group || is_user) &&
     # User is authenticated
     authenticated? &&
-    # Have to be a basic level at least
-    (is_group || @user.has_trust_level?(SiteSetting.min_trust_to_send_messages) || notify_moderators) &&
     # User disabled private message
     (is_staff? || is_group || target.user_option.allow_private_messages) &&
-    # PMs are enabled
-    (is_staff? || SiteSetting.enable_personal_messages || notify_moderators) &&
+    # User can send PMs, this can be covered by trust levels as well via AUTO_GROUPS
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+    (is_staff? || (@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map) || SiteSetting.enable_personal_messages) || notify_moderators) &&
     # Can't send PMs to suspended users
     (is_staff? || is_group || !target.suspended?) &&
     # Check group messageable level
@@ -467,7 +474,9 @@ class Guardian
     # User is authenticated
     return false if !authenticated?
     # User is trusted enough
-    SiteSetting.enable_personal_messages && @user.has_trust_level_or_staff?(SiteSetting.min_trust_to_send_email_messages)
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+    (@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map) || SiteSetting.enable_personal_messages) &&
+      @user.has_trust_level_or_staff?(SiteSetting.min_trust_to_send_email_messages)
   end
 
   def can_export_entity?(entity)
diff --git a/lib/guardian/group_guardian.rb b/lib/guardian/group_guardian.rb
index 1a869e4e7fe..e5df8bfdc66 100644
--- a/lib/guardian/group_guardian.rb
+++ b/lib/guardian/group_guardian.rb
@@ -33,8 +33,12 @@ module GroupGuardian
   def can_see_group_messages?(group)
     return true if is_admin?
     return true if is_moderator? && group.id == Group::AUTO_GROUPS[:moderators]
+    return false if user.blank?
 
-    SiteSetting.enable_personal_messages? && group.users.include?(user)
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+    (SiteSetting.enable_personal_messages ||
+      user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map)) &&
+      group.users.include?(user)
   end
 
   def can_associate_groups?
diff --git a/lib/guardian/post_guardian.rb b/lib/guardian/post_guardian.rb
index 15a3c6f3694..a4f9e536ecf 100644
--- a/lib/guardian/post_guardian.rb
+++ b/lib/guardian/post_guardian.rb
@@ -50,10 +50,10 @@ module PostGuardian
         (!SiteSetting.allow_flagging_staff?) &&
         post&.user&.staff?
 
+      # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
       if action_key == :notify_user &&
-         (!SiteSetting.enable_personal_messages? ||
-         !@user.has_trust_level?(SiteSetting.min_trust_to_send_messages))
-
+          (!@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map) ||
+           !SiteSetting.enable_personal_messages)
         return false
       end
 
diff --git a/lib/guardian/tag_guardian.rb b/lib/guardian/tag_guardian.rb
index 4f14858f013..8d445fca9c4 100644
--- a/lib/guardian/tag_guardian.rb
+++ b/lib/guardian/tag_guardian.rb
@@ -15,6 +15,7 @@ module TagGuardian
     return false if @user.blank?
     return true if @user == Discourse.system_user
 
+    # TODO (martin) Change to pm_tags_allowed_for_groups_map
     group_ids = SiteSetting.pm_tags_allowed_for_groups.to_s.split("|").map(&:to_i)
     group_ids.include?(Group::AUTO_GROUPS[:everyone]) || @user.group_users.exists?(group_id: group_ids)
   end
diff --git a/lib/guardian/topic_guardian.rb b/lib/guardian/topic_guardian.rb
index 06141292247..5d974bad280 100644
--- a/lib/guardian/topic_guardian.rb
+++ b/lib/guardian/topic_guardian.rb
@@ -183,7 +183,8 @@ module TopicGuardian
   end
 
   def can_convert_topic?(topic)
-    return false unless SiteSetting.enable_personal_messages?
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+    return false unless SiteSetting.enable_personal_messages? || @user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map)
     return false if topic.blank?
     return false if topic.trashed?
     return false if topic.is_category_topic?
diff --git a/lib/site_setting_extension.rb b/lib/site_setting_extension.rb
index 8953e4fc6f2..0a5699bbc1d 100644
--- a/lib/site_setting_extension.rb
+++ b/lib/site_setting_extension.rb
@@ -542,6 +542,15 @@ module SiteSettingExtension
       end
     end
 
+    # Any group_list setting, e.g. personal_message_enabled_groups, will have
+    # a getter defined with _map on the end, e.g. personal_message_enabled_groups_map,
+    # to avoid having to manually split and convert to integer for these settings.
+    if type_supervisor.get_type(name) == :group_list
+      define_singleton_method("#{clean_name}_map") do
+        self.public_send(clean_name).to_s.split("|").map(&:to_i)
+      end
+    end
+
     define_singleton_method "#{clean_name}?" do
       self.public_send clean_name
     end
@@ -592,5 +601,4 @@ module SiteSettingExtension
   def logger
     Rails.logger
   end
-
 end
diff --git a/lib/site_settings/deprecated_settings.rb b/lib/site_settings/deprecated_settings.rb
index cb8f352287c..8690c79ae90 100644
--- a/lib/site_settings/deprecated_settings.rb
+++ b/lib/site_settings/deprecated_settings.rb
@@ -7,6 +7,8 @@ module SiteSettings::DeprecatedSettings
     # [<old setting>, <new_setting>, <override>, <version to drop>]
     ['search_tokenize_chinese_japanese_korean', 'search_tokenize_chinese', true, '2.9'],
     ['default_categories_regular', 'default_categories_normal', true, '3.0'],
+    ['min_trust_to_send_messages', 'personal_message_enabled_groups', false, '3.0'],
+    ['enable_personal_messages', 'personal_message_enabled_groups', false, '3.0'],
   ]
 
   def setup_deprecated_methods
diff --git a/lib/topic_query.rb b/lib/topic_query.rb
index 3f7a5aecb44..4e863226068 100644
--- a/lib/topic_query.rb
+++ b/lib/topic_query.rb
@@ -172,7 +172,11 @@ class TopicQuery
   def list_related_for(topic, pm_params: nil)
     return if !topic.private_message?
     return if @user.blank?
-    return if !SiteSetting.enable_personal_messages?
+
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
+    if !SiteSetting.enable_personal_messages || !@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map)
+      return
+    end
 
     builder = SuggestedTopicsBuilder.new(topic)
     pm_params = pm_params || get_pm_params(topic)
@@ -197,10 +201,13 @@ class TopicQuery
   # Return a list of suggested topics for a topic
   def list_suggested_for(topic, pm_params: nil)
 
+    # TODO (martin) Remove enable_personal_messages here once plugins have been changed.
     # Don't suggest messages unless we have a user, and private messages are
     # enabled.
-    return if topic.private_message? &&
-      (@user.blank? || !SiteSetting.enable_personal_messages?)
+    if topic.private_message? && (
+        @user.blank? || !@user.in_any_groups?(SiteSetting.personal_message_enabled_groups_map || !SiteSetting.enable_personal_messages))
+      return
+    end
 
     builder = SuggestedTopicsBuilder.new(topic)
 
diff --git a/lib/validators/personal_message_enabled_groups_validator.rb b/lib/validators/personal_message_enabled_groups_validator.rb
new file mode 100644
index 00000000000..8def3bc3e5d
--- /dev/null
+++ b/lib/validators/personal_message_enabled_groups_validator.rb
@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class PersonalMessageEnabledGroupsValidator
+
+  def initialize(opts = {})
+    @opts = opts
+  end
+
+  def valid_value?(val)
+    val.present? && val != ""
+  end
+
+  def error_message
+    I18n.t("site_settings.errors.personal_message_enabled_groups_invalid")
+  end
+end
diff --git a/spec/lib/admin_user_index_query_spec.rb b/spec/lib/admin_user_index_query_spec.rb
index 4bce40f83e4..71fe1856d8c 100644
--- a/spec/lib/admin_user_index_query_spec.rb
+++ b/spec/lib/admin_user_index_query_spec.rb
@@ -80,10 +80,12 @@ RSpec.describe AdminUserIndexQuery do
     TrustLevel.levels.each do |key, value|
       it "finds user with trust #{key}" do
         user = Fabricate(:user, trust_level: value)
+
+        next if !TrustLevel.valid?(value + 1)
         Fabricate(:user, trust_level: value + 1)
 
         query = ::AdminUserIndexQuery.new(query: key.to_s)
-        expect(real_users(query)).to eq([user])
+        expect(real_users(query).to_a).to eq([user])
       end
     end
 
diff --git a/spec/lib/guardian_spec.rb b/spec/lib/guardian_spec.rb
index cdcab4d22cb..3159e3bfb48 100644
--- a/spec/lib/guardian_spec.rb
+++ b/spec/lib/guardian_spec.rb
@@ -14,17 +14,21 @@ RSpec.describe Guardian do
   fab!(:automatic_group) { Fabricate(:group, automatic: true) }
   fab!(:plain_category) { Fabricate(:category) }
 
-  let(:trust_level_0) { build(:user, trust_level: 0) }
-  let(:trust_level_1) { build(:user, trust_level: 1) }
-  let(:trust_level_2) { build(:user, trust_level: 2) }
-  let(:trust_level_3) { build(:user, trust_level: 3) }
-  let(:trust_level_4)  { build(:user, trust_level: 4) }
-  let(:another_admin) { build(:admin) }
-  let(:coding_horror) { build(:coding_horror) }
+  fab!(:trust_level_0) { Fabricate(:user, trust_level: 0) }
+  fab!(:trust_level_1) { Fabricate(:user, trust_level: 1) }
+  fab!(:trust_level_2) { Fabricate(:user, trust_level: 2) }
+  fab!(:trust_level_3) { Fabricate(:user, trust_level: 3) }
+  fab!(:trust_level_4)  { Fabricate(:user, trust_level: 4) }
+  fab!(:another_admin) { Fabricate(:admin) }
+  fab!(:coding_horror) { Fabricate(:coding_horror) }
 
   let(:topic) { build(:topic, user: user) }
   let(:post) { build(:post, topic: topic, user: topic.user) }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   it 'can be created without a user (not logged in)' do
     expect { Guardian.new }.not_to raise_error
   end
@@ -173,16 +177,11 @@ RSpec.describe Guardian do
       end
     end
 
-    it "returns false for notify_user if private messages are disabled" do
+    it "returns false for notify_user if user is not in any group that can send personal messages" do
+      user = Fabricate(:user)
       SiteSetting.enable_personal_messages = false
-      user.trust_level = TrustLevel[2]
-      expect(Guardian.new(user).post_can_act?(post, :notify_user)).to be_falsey
-    end
-
-    it "returns false for notify_user if private messages are enabled but threshold not met" do
-      SiteSetting.enable_personal_messages = true
-      SiteSetting.min_trust_to_send_messages = 2
-      user.trust_level = TrustLevel[1]
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
+      user.change_trust_level!(1)
       expect(Guardian.new(user).post_can_act?(post, :notify_user)).to be_falsey
     end
 
@@ -268,7 +267,10 @@ RSpec.describe Guardian do
     end
 
     it "returns false when you are untrusted" do
-      user.trust_level = TrustLevel[0]
+      SiteSetting.enable_personal_messages = false
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_2]
+      user.update!(trust_level: TrustLevel[0])
+      Group.user_trust_level_change!(user.id, TrustLevel[0])
       expect(Guardian.new(user).can_send_private_message?(another_user)).to be_falsey
     end
 
@@ -277,16 +279,25 @@ RSpec.describe Guardian do
     end
 
     it "disallows pms to other users if trust level is not met" do
-      SiteSetting.min_trust_to_send_messages = TrustLevel[2]
-      user.trust_level = TrustLevel[1]
+      SiteSetting.enable_personal_messages = false
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_2]
+      user.update!(trust_level: TrustLevel[1])
+      Group.user_trust_level_change!(user.id, TrustLevel[1])
       expect(Guardian.new(user).can_send_private_message?(another_user)).to be_falsey
     end
 
-    context "when enable_personal_messages is false" do
-      before { SiteSetting.enable_personal_messages = false }
+    context "when personal_message_enabled_groups does not contain the user" do
+      let(:group) { Fabricate(:group) }
+      before do
+        SiteSetting.personal_message_enabled_groups = group.id
+        SiteSetting.enable_personal_messages = false
+      end
 
       it "returns false if user is not staff member" do
         expect(Guardian.new(trust_level_4).can_send_private_message?(another_user)).to be_falsey
+        GroupUser.create(user: trust_level_4, group: group)
+        trust_level_4.reload
+        expect(Guardian.new(trust_level_4).can_send_private_message?(another_user)).to be_truthy
       end
 
       it "returns true for staff member" do
@@ -345,6 +356,8 @@ RSpec.describe Guardian do
 
     it "allows TL0 to message group with messageable_level = everyone" do
       group.update!(messageable_level: Group::ALIAS_LEVELS[:everyone])
+      SiteSetting.enable_personal_messages = false
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_0]
       expect(Guardian.new(trust_level_0).can_send_private_message?(group)).to eq(true)
       expect(Guardian.new(user).can_send_private_message?(group)).to eq(true)
     end
@@ -356,6 +369,8 @@ RSpec.describe Guardian do
       group.add(user)
       expect(Guardian.new(user).can_send_private_message?(group)).to eq(true)
 
+      SiteSetting.enable_personal_messages = false
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_0]
       expect(Guardian.new(trust_level_0).can_send_private_message?(group)).to eq(false)
 
       #  group membership trumps min_trust_to_send_messages setting
@@ -565,11 +580,6 @@ RSpec.describe Guardian do
         expect(Guardian.new(group_owner).can_invite_to?(group_private_topic)).to be_truthy
       end
 
-      it 'returns true for normal user when inviting to topic and PM disabled' do
-        SiteSetting.enable_personal_messages = false
-        expect(Guardian.new(trust_level_2).can_invite_to?(topic)).to be_truthy
-      end
-
       it 'return true for normal users even if must_approve_users' do
         SiteSetting.must_approve_users = true
         expect(Guardian.new(user).can_invite_to?(topic)).to be_truthy
@@ -617,10 +627,14 @@ RSpec.describe Guardian do
     end
 
     describe "private messages" do
-      fab!(:user) { Fabricate(:user, trust_level: TrustLevel[2]) }
-      fab!(:user) { Fabricate(:user, trust_level: SiteSetting.min_trust_level_to_allow_invite) }
+      fab!(:user) { Fabricate(:user) }
       fab!(:pm) { Fabricate(:private_message_topic, user: user) }
 
+      before do
+        user.change_trust_level!(SiteSetting.min_trust_level_to_allow_invite)
+        moderator.change_trust_level!(SiteSetting.min_trust_level_to_allow_invite)
+      end
+
       context "when private messages are disabled" do
         it "allows an admin to invite to the pm" do
           expect(Guardian.new(admin).can_invite_to?(pm)).to be_truthy
@@ -628,9 +642,10 @@ RSpec.describe Guardian do
         end
       end
 
-      context "when private messages are disabled" do
+      context "when user does not belong to personal_message_enabled_groups" do
         before do
           SiteSetting.enable_personal_messages = false
+          SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
         end
 
         it "doesn't allow a regular user to invite" do
@@ -1307,9 +1322,10 @@ RSpec.describe Guardian do
       expect(Guardian.new(admin).can_convert_topic?(topic)).to be_truthy
     end
 
-    it 'returns false when personal messages are disabled' do
+    it 'returns false when user is not in personal_message_enabled_groups' do
       SiteSetting.enable_personal_messages = false
-      expect(Guardian.new(admin).can_convert_topic?(topic)).to be_falsey
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_4]
+      expect(Guardian.new(user).can_convert_topic?(topic)).to be_falsey
     end
   end
 
diff --git a/spec/lib/post_action_creator_spec.rb b/spec/lib/post_action_creator_spec.rb
index 8343f730964..6c66c50d1c8 100644
--- a/spec/lib/post_action_creator_spec.rb
+++ b/spec/lib/post_action_creator_spec.rb
@@ -6,6 +6,10 @@ RSpec.describe PostActionCreator do
   fab!(:post) { Fabricate(:post) }
   let(:like_type_id) { PostActionType.types[:like] }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   describe "rate limits" do
     before do
       RateLimiter.clear_all!
diff --git a/spec/lib/topic_creator_spec.rb b/spec/lib/topic_creator_spec.rb
index 0b448a7cc17..6ce006ed851 100644
--- a/spec/lib/topic_creator_spec.rb
+++ b/spec/lib/topic_creator_spec.rb
@@ -421,9 +421,8 @@ RSpec.describe TopicCreator do
           expect(TopicCreator.create(user, Guardian.new(user), pm_valid_attrs)).to be_valid
         end
 
-        it "enable_personal_messages setting should not be checked when sending private message to staff via flag" do
-          SiteSetting.enable_personal_messages = false
-          SiteSetting.min_trust_to_send_messages = TrustLevel[4]
+        it "personal_message_enabled_groups setting should not be checked when sending private messages to staff via flag" do
+          SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
           expect(TopicCreator.create(user, Guardian.new(user), pm_valid_attrs.merge(subtype: TopicSubtype.notify_moderators))).to be_valid
         end
       end
@@ -442,8 +441,9 @@ RSpec.describe TopicCreator do
           end.to raise_error(ActiveRecord::Rollback)
         end
 
-        it "min_trust_to_send_messages setting should be checked when sending private message" do
-          SiteSetting.min_trust_to_send_messages = TrustLevel[4]
+        it "personal_message_enabled_groups setting should be checked when sending private message" do
+          SiteSetting.enable_personal_messages = false
+          SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_4]
 
           expect do
             TopicCreator.create(user, Guardian.new(user), pm_valid_attrs)
diff --git a/spec/lib/topic_query_spec.rb b/spec/lib/topic_query_spec.rb
index 7ff1fe9bd28..b18f4fd5892 100644
--- a/spec/lib/topic_query_spec.rb
+++ b/spec/lib/topic_query_spec.rb
@@ -1091,12 +1091,18 @@ RSpec.describe TopicQuery do
       TopicUser.update_last_read(user, topic, post_number, post_number, 10000)
     end
 
-    it 'returns the correct suggestions' do
+    before do
+      user.change_trust_level!(4)
+      sender.change_trust_level!(4)
+    end
 
+    it 'returns the correct suggestions' do
       pm_to_group = create_pm(sender, target_group_names: [group_with_user.name])
       pm_to_user = create_pm(sender, target_usernames: [user.username])
 
-      old_unrelated_pm = create_pm(target_usernames: [user.username])
+      other_user = Fabricate(:user)
+      other_user.change_trust_level!(1)
+      old_unrelated_pm = create_pm(other_user, target_usernames: [user.username])
       read(user, old_unrelated_pm, 1)
 
       related_by_user_pm = create_pm(sender, target_usernames: [user.username])
@@ -1113,7 +1119,7 @@ RSpec.describe TopicQuery do
         eq([related_by_user_pm.id])
       )
 
-      SiteSetting.enable_personal_messages = false
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
       expect(TopicQuery.new(user).list_related_for(pm_to_group)).to be_blank
       expect(TopicQuery.new(user).list_related_for(pm_to_user)).to be_blank
     end
@@ -1236,6 +1242,8 @@ RSpec.describe TopicQuery do
         before do
           group.add(group_user)
           another_group.add(user)
+          Group.user_trust_level_change!(user.id, user.trust_level)
+          Group.user_trust_level_change!(group_user.id, group_user.trust_level)
         end
 
         context 'as user not part of group' do
diff --git a/spec/models/post_action_spec.rb b/spec/models/post_action_spec.rb
index 746f4fc55f0..c24c8d17ac5 100644
--- a/spec/models/post_action_spec.rb
+++ b/spec/models/post_action_spec.rb
@@ -800,6 +800,7 @@ RSpec.describe PostAction do
   end
 
   it "prevents user to act twice at the same time" do
+    Group.refresh_automatic_groups!
     # flags are already being tested
     all_types_except_flags = PostActionType.types.except(*PostActionType.flag_types_without_custom.keys)
     all_types_except_flags.values.each do |action|
diff --git a/spec/models/topic_spec.rb b/spec/models/topic_spec.rb
index 7a8ddeafb52..3dcc50f8782 100644
--- a/spec/models/topic_spec.rb
+++ b/spec/models/topic_spec.rb
@@ -830,7 +830,8 @@ RSpec.describe Topic do
 
         context "when PMs are enabled for TL3 or higher only" do
           before do
-            SiteSetting.min_trust_to_send_messages = 3
+            SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_4]
+            SiteSetting.enable_personal_messages = false
           end
 
           it 'should raise error' do
@@ -882,6 +883,10 @@ RSpec.describe Topic do
       end
 
       describe 'by email' do
+        before do
+          Group.refresh_automatic_groups!
+        end
+
         it 'should be able to invite a user' do
           expect(topic.invite(user, user1.email)).to eq(true)
           expect(topic.allowed_users).to include(user1)
diff --git a/spec/models/trust_level3_requirements_spec.rb b/spec/models/trust_level3_requirements_spec.rb
index 9f8dfa3d150..984714f76f3 100644
--- a/spec/models/trust_level3_requirements_spec.rb
+++ b/spec/models/trust_level3_requirements_spec.rb
@@ -2,7 +2,7 @@
 
 RSpec.describe TrustLevel3Requirements do
 
-  let(:user) { Fabricate.build(:user) }
+  fab!(:user) { Fabricate(:user) }
   subject(:tl3_requirements) { described_class.new(user) }
   fab!(:moderator) { Fabricate(:moderator) }
 
diff --git a/spec/requests/groups_controller_spec.rb b/spec/requests/groups_controller_spec.rb
index 397dd43c9ed..262083c0128 100644
--- a/spec/requests/groups_controller_spec.rb
+++ b/spec/requests/groups_controller_spec.rb
@@ -375,23 +375,6 @@ RSpec.describe GroupsController do
       expect(response.headers['X-Robots-Tag']).to eq('noindex')
     end
 
-    it "returns the right response for 'messageable' field" do
-      sign_in(user)
-      group.update!(messageable_level: Group::ALIAS_LEVELS[:everyone])
-
-      get "/groups/#{group.name}.json"
-
-      expect(response.status).to eq(200)
-      expect(response.parsed_body['group']['messageable']).to eq(true)
-
-      SiteSetting.enable_personal_messages = false
-
-      get "/groups/#{group.name}.json"
-
-      expect(response.status).to eq(200)
-      expect(response.parsed_body['group']['messageable']).to eq(false)
-    end
-
     context 'as an admin' do
       it "returns the right response" do
         sign_in(admin)
@@ -631,6 +614,7 @@ RSpec.describe GroupsController do
 
   describe '#messageable' do
     it "should return the right response" do
+      user.change_trust_level!(1)
       sign_in(user)
 
       get "/groups/#{group.name}/messageable.json"
@@ -650,6 +634,7 @@ RSpec.describe GroupsController do
       body = response.parsed_body
       expect(body["messageable"]).to eq(true)
 
+      SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
       SiteSetting.enable_personal_messages = false
 
       get "/groups/#{group.name}/messageable.json"
diff --git a/spec/requests/list_controller_spec.rb b/spec/requests/list_controller_spec.rb
index 537542eee7d..cc6b941cd84 100644
--- a/spec/requests/list_controller_spec.rb
+++ b/spec/requests/list_controller_spec.rb
@@ -191,12 +191,14 @@ RSpec.describe ListController do
   describe '#private_messages_group' do
     fab!(:user) { Fabricate(:user) }
 
-    describe 'with personal_messages disabled' do
+    describe 'when user not in personal_message_enabled_groups group' do
       let!(:topic) { Fabricate(:private_message_topic, allowed_groups: [group]) }
 
       before do
         group.add(user)
+        SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:staff]
         SiteSetting.enable_personal_messages = false
+        Group.refresh_automatic_groups!
       end
 
       it 'should display group private messages for an admin' do
diff --git a/spec/requests/post_actions_controller_spec.rb b/spec/requests/post_actions_controller_spec.rb
index bfa0544d0d4..8fca3ef9159 100644
--- a/spec/requests/post_actions_controller_spec.rb
+++ b/spec/requests/post_actions_controller_spec.rb
@@ -4,6 +4,10 @@ RSpec.describe PostActionsController do
   fab!(:user) { Fabricate(:user) }
   fab!(:coding_horror) { Fabricate(:coding_horror) }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   describe '#destroy' do
     fab!(:post) { Fabricate(:post, user: coding_horror) }
 
diff --git a/spec/requests/topics_controller_spec.rb b/spec/requests/topics_controller_spec.rb
index 0ed754a064a..7f84e4919a4 100644
--- a/spec/requests/topics_controller_spec.rb
+++ b/spec/requests/topics_controller_spec.rb
@@ -36,6 +36,24 @@ RSpec.describe TopicsController do
 
   fab!(:tag) { Fabricate(:tag) }
 
+  before do
+    [
+      user,
+      user_2,
+      post_author1,
+      post_author2,
+      post_author3,
+      post_author4,
+      post_author5,
+      post_author6,
+      trust_level_0,
+      trust_level_1,
+      trust_level_4
+    ].each do |u|
+      Group.user_trust_level_change!(u.id, u.trust_level)
+    end
+  end
+
   describe '#wordpress' do
     before do
       sign_in(moderator)
@@ -4115,6 +4133,7 @@ RSpec.describe TopicsController do
 
         before do
           SiteSetting.max_allowed_message_recipients = 2
+          Group.refresh_automatic_groups!
         end
 
         it "doesn't allow normal users to invite" do
diff --git a/spec/requests/users_controller_spec.rb b/spec/requests/users_controller_spec.rb
index 88ff88ce945..ff74b1f41fa 100644
--- a/spec/requests/users_controller_spec.rb
+++ b/spec/requests/users_controller_spec.rb
@@ -13,6 +13,10 @@ RSpec.describe UsersController do
   fab!(:moderator) { Fabricate(:moderator) }
   fab!(:inactive_user) { Fabricate(:inactive_user) }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   # Unfortunately, there are tests that depend on the user being created too
   # late for fab! to work.
   let(:user_deferred) { Fabricate(:user) }
@@ -5858,19 +5862,13 @@ RSpec.describe UsersController do
         expect(response.status).to eq(403)
       end
 
-      it "responds with 403 if private messages are disabled and the user isn't staff" do
-        SiteSetting.enable_personal_messages = false
+      it "responds with 403 if personal_message_enabled_groups does not include the user and the user isn't staff" do
+        SiteSetting.personal_message_enabled_groups = Group::AUTO_GROUPS[:trust_level_4]
+        user.update(trust_level: 1)
         get "/u/#{user.username}/user-menu-private-messages"
         expect(response.status).to eq(403)
       end
 
-      it "doesn't respond with 403 if private messages are disabled and the user is staff" do
-        SiteSetting.enable_personal_messages = false
-        user.update!(moderator: true)
-        get "/u/#{user.username}/user-menu-private-messages"
-        expect(response.status).to eq(200)
-      end
-
       it "sends an array of unread private_message notifications" do
         get "/u/#{user.username}/user-menu-private-messages"
         expect(response.status).to eq(200)
diff --git a/spec/serializers/post_serializer_spec.rb b/spec/serializers/post_serializer_spec.rb
index 23c3123ad7a..266507082bf 100644
--- a/spec/serializers/post_serializer_spec.rb
+++ b/spec/serializers/post_serializer_spec.rb
@@ -3,6 +3,10 @@
 RSpec.describe PostSerializer do
   fab!(:post) { Fabricate(:post) }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   context "with a post with lots of actions" do
     fab!(:actor) { Fabricate(:user) }
     fab!(:admin) { Fabricate(:admin) }
diff --git a/spec/serializers/topic_view_serializer_spec.rb b/spec/serializers/topic_view_serializer_spec.rb
index 75681814d82..d55b848dcb2 100644
--- a/spec/serializers/topic_view_serializer_spec.rb
+++ b/spec/serializers/topic_view_serializer_spec.rb
@@ -97,6 +97,11 @@ RSpec.describe TopicViewSerializer do
   end
 
   describe '#suggested_topics' do
+    before do
+      SiteSetting.enable_personal_messages = false
+      Group.refresh_automatic_groups!
+    end
+
     fab!(:topic2) { Fabricate(:topic) }
 
     before do
@@ -165,6 +170,10 @@ RSpec.describe TopicViewSerializer do
     fab!(:pm) { Fabricate(:private_message_post).topic }
     fab!(:group) { Fabricate(:group) }
 
+    before do
+      Group.refresh_automatic_groups!
+    end
+
     it 'is nil for a regular topic' do
       json = serialize_topic(topic, user)
 
diff --git a/spec/services/user_merger_spec.rb b/spec/services/user_merger_spec.rb
index d1c69c6364d..1a289365640 100644
--- a/spec/services/user_merger_spec.rb
+++ b/spec/services/user_merger_spec.rb
@@ -13,6 +13,10 @@ RSpec.describe UserMerger do
   fab!(:p5) { Fabricate(:post) }
   fab!(:p6) { Fabricate(:post) }
 
+  before do
+    Group.refresh_automatic_groups!
+  end
+
   def merge_users!(source = nil, target =  nil)
     source ||= source_user
     target ||= target_user