Personally I just use a macro in ISBoxer for my battleresses:

Code:
/cast [@{SLOT1},dead] Rebirth; [@{SLOT2},dead] Rebirth; [@{SLOT3},dead] Rebirth; [@{SLOT4},dead] Rebirth; [@{SLOT5},dead] Rebirth
The slots get replaced with the name of the character in each character slot, so it'll work with any team. And since there is a condition of "dead" for each part, it'll just target any character that is dead at the time. I found this rather useful so I don't have to actually target the character and can just have it all under a single keybind.

Works fairly well. If you're worried about simultaneous casting using up multiple battle resses, then I guess you could round-robin it.