Admin Panel -> Permissions -> Add New User Group
Note: You may need to adjust the permissions of the newly added group.
In the "FoF Default Group" extension, set the group you just added as the default.
In the "FoF Default User Preferences" extension, enable the "Group Mention Emails" setting.
Install the "Mentions" extension. By default, mention permissions for groups are granted to administrators.
After this, for example, when a forum administrator shares an announcement topic, they can mention members with the @Group tag, and an email will be sent to all members.
You can also do this by adding multiple groups. This usage should function similarly to Discord's @everyone feature, but with @badge (the special tags assigned to members).