I'm about to start tri-boxing (then move up to 5 boxing when I get everything down) I have a question about substituting in alts into the rotation.

On my main account I have a few alts. For the new setup I'm planning on starting up 3 shaman. My question: Is there a simple solution to substituting in my mage or hunter for a dungeon run. (ie. normal setup 3 shaman, occasional setup 2 shaman and 1 mage) For gear farming.
Macros would be all screwed up. Would it be easier to just have the mage follow one of the shaman? and not participate? Is there a simple solution?
Just wondering if anyone else has tried this.
Thanks