I am running 3 Warlocks

Main warlock selects target
I press my petattack macro key

the macro (for the 2 following locks) is like this:
/assist MainWarlock
/petattack

For the Main Warlock the Macro is
/petattack

I'm finding, especially in instances with many nasty mobs around, that sometimes one of the pets of the 2 following locks will run off into the instance and attack another mob (maybe the next closest?) instead of the one targeted by the main . Pet then dies and brings 5 billion mobs to slay my team. Great.

So wny ideas what is wrong with the macro, its a pretty basic one right?

Thanks for your advice.