Selective Spell( Shining South, p. 21)
You can screen allies from the effects of your area spells.
Any other Metamagic Feat,
You can modify an area spell so that it does not affect one designated creature within it's area. All other creatures in the spell's area are affected normally. Selective spell has no effect on target or effect spells. A Spelective spell uses a slot one level higher than the spells normal level.