Automatically join members to groups based on user profile fields. Requires BuddyPress
Automatically join a member to a group based on a profile field. For example, say you have a profile field where the person selects his state from a drop down list. If he selects, New York, he'll be automatically added to the group New York. Or, if you have a profile field for "Favorite Animal" and the member selects "Dog", you could automatically have him become a member of the group "Dog's Rule" and "Best Dog Food".