Are they the owners of their groups (identified by star next to their name in group members list in Persona)? Because even if they're not moderators I believe group owners are able to add people to their group.
Default Following Member
Is there anyway I can set my Forum so that new members automatically follow me, without having to click set this up themselves?
Is your name Tom? Did you create MySpace? he he he...
In any case, looks like you'd want to create a plugin to do this... listening for the hook for user