BuddyPress.org

Use a single command to mention a group of members on your BuddyPress site.

Usage:

• The @group command can be used within a group to mention all of that group’s members
• The @mod command can be used within a group to mention that group’s moderators
• The @friends command can be used anywhere. If used within a group, friends who are not members of that group will not be notified

https://wordpress.org/plugins/crowdmentions/