Is that group focus in a region area? If not, then that group will merely for game discussion and info sharing or just "signed if you play Hunted" because the ping issue of players come from different region. For me, East-Asia.
*edit: I still join-in this group anyway (why not?). And FYI, as my Steam using experience...you have to edit the group permissions for member to set up a event on their own via this group. But you say it's a "CLAN" so it might not proper to set that public.