Bp Group Control

BP Group Control is a set of tools that gives group admins the ability to create new members for their groups, add existing users to their groups, directly delete members, and assign their members an identifying tag ( the group name ) that shows up next to their display name on their profile and directories. These features are supported by a rich options page that allows site admins to tweak the permission settings for these abilities.

Be careful with this plugin! Make sure you trust your group admins with the power you grant them.

You can choose to have different parts of this plugin active for public vs private groups as well.