Permission can be available only in channel groups permissions, when somebody has Channel Admin on this channel so when he reconnect he will join default on this channel what he has the rank.
If somebody has Channel Admin on the channels he will randomly connect to this channel what is on the top.
I think this function will be good on public servers because you can set all users with rannk Voice, Operator and Channel Admin will connect into his channels.
I know this option is in bookmarks but nobody use this because nobody know how to do that correctly.