That's not how any 24 man raid works that I can think of, the one that jumps out the most is last boss of Void Ark. At the split, the lamia (middle) has aggro on B tank. Snake on her left has hate on A, snake on right has aggro on C.
Back on subject of splitting the player base for DF content, it would drive bads out of the game. That may sound like a good thing at first, until you have to put up with the longer queue times that comes along with it, and less content due to fewer subscribers.
