Example:
You have server groups for all kinds of games in your clan.
Diablo III, League of Legends, CS:Source etc etc...
When you make a channel you can only set joinpower to join the channel.
I can put joinpower for the Diablo III server group on 60, League of Legends on 61 and CS:Source on 62.
And the channels: Diablo III, needed power of 60. League of Legends needed power of 61 and CS:Source 62.
So a Diablo III member cannot join the League of Legends channel or the CS:Source channel.
But a member with the CS:Source servergroup can join ALL Channels.
I think teamspeak will be much better with my idea:
To have in the: EDIT CHANNEL option an extra tab with: Allow or something like that.
Example: the Diablo III channel.
Only allow: Diablo III Server Group. all other server groups are not allowed to join this channel now. no joinpower needed. just allowed server groups.
Example: