Yes, I am sorry. I think understand a *bit* of what you are wanting. I am just not exactly sure where to find it if that makes any sense. All I can see that has to do with groups is phpbb_user_groups which from what I read is for Users groups and then phpbb_acl_groups which I believe is for permission roles and/or individual permissions assigned to groups.
I am sorry I am not very clear on all of this. The whole phpbb thing I am pretty new to and still trying to figure it all out. Thank you for working with me!