cool, some great beat...
i would help, but my license is off...
btw i can help a bit, telling what to do with this.
1- for each listing, like memberslist and buddies, where there is SELECT ... FROM " .TABLEPREFIX. "user, you need to merge (LEFT_JOIN) with the usergroup table and filter if the member are in the banned group... if yes, not display, simply...
2- if you need something more efficient, you can also make a UPDATE of the buddylist by removing the person from everyone's list when he goes BANNED, but the problem is when he comes back... can't add it back...