[andrewas]

SI:abjuration will keep your mages on the surface.

Fighters can use prot from undead (*AFTER* the transformation, if an undead has a scripted convo before death, prot from undead breaks the game), or protection from magic, if you want to be cheesy.

ALso, keep in mind that lich has limited targetting abilities, he will choose the closest target and keep firing on that. If that target is a protected mage, your tanks can safely walk up and make lich dust.