For your big button

/target [target=Brain, nodead]; [target=Toontwo, nodead]; [target=ToonThree, nodead]; [target=ToonFour, nodead]; [target=ToonFive, nodead];[target=Brain]
/follow

For attacks/heals

/cast [target=targettarget] [] InsertSpellHere

This works for heals as well, if the first condition returns a harm enemy, the second condition fits - so you'll heal the leader. If the leader has a helpful target, everyone will heal that person.

If your main dies, go to window #2, hit your big button - everyone will go to the new guy and target him - no need for seperate macros per toon.

The only condition is they need to be in the same group/raid. They do NOT need to be in the same group in a raid.