AI of AoE spells.

I am doing AI scripting for an AoS map at the moment. And i am wondering about how can i make the computer use spells like Blizzard and Flamestrike hitting the largest amount of enemies and NOT hitting his allies?

I have seen the computer make all the necessary calculations and aim his spells automatically, but i want a way to make him do it when i order him to.

AI for AoE spells..?
Someone?

Anyone???

well, i dont really make ai but i guess you could pick a unit in range of the desired caster then get how many units are enimies of the caster within the AOE of that unit and how many are allies of the caster. then set up a priority system like an enemie adds 1 point to this target but an allie takes away 1.75 and take maybe 5 test like this and order him to attack the spot with the most points for it.