Change:
Code:
/click ActionButton12
/cast [nomod,target=target] [target=targettarget] Healing wave
to:
Code:
/click ActionButton12
/cast [target=targettarget][] Healing wave
and just pre-target your main before the fight. The toons will cast on the mains target if he has one that is friendly and a valid target, or heal the main if not. I use targettargettarget a lot of times to heal as well, this chain will heal whoever has pulled aggro on the mains targeted mob.