Quote Originally Posted by Contents
the easiest method.... Click on each screen and manually place/cast flamestrike.

I believe there is a way to have it centered on a targeted mob, but I can't recall how to do it.
it involves using the [target=focus] modifier but that is all I know. There was another similiar thread here that mentioned it. The suggestion was to use center the mouse on all minions so that they had the target mouse over and then use a macro to cast the spell with the target being the focus.