I just found one plugin “Invite Anyone” that allows group admin\moderator to invite any site users to the group. This plugin also allows you to invite people to join the site & group(s) through email.
I am new to BuddyPress as well. From what I have tested, you can only add new members to group from backend Dashboard “Groups” menu. By default, this “Groups” menu is only accessible by site admin.
However, you can setup group admin and moderator. Both roles can invite friends to the group. This requires the friends feature enabled. Group admin\moderator have to add other users to their friend list. Then they can invite these friends of their own to the group.
I hope this help!
I also try to give group admin the ability to add new member directly (instead through dashboard “Groups” menu or invitation), but no luck so far. If anyone knows there is a plugin can do so, please let me know.
