Selective Spell (Metamagic) Your allies need not fear friendly fire.
Prerequisite: Spellcraft 10 ranks.
Benefit: When casting a selective spell with an area effect and a duration of instantaneous, you can choose a number of targets in the area equal to the ability score modifier used to determine bonus spells of the same type (Charisma for bards, oracles, paladins, sorcerers, and summoners; Intelligence for witches and wizards; Wisdom for clerics, druids, inquisitors, and rangers). These targets are excluded from the effects of your spell. A selective spell uses up a spell slot one level higher than the spell's actual level. Spells that do not have an area of effect do not benefit from this feat.
Metamagic, Selective
Aura strong (no school); CL 17th
Slot none; Price 3,000 gp (lesser), 11,000 gp (normal), 24,500 gp (greater); Weight 5 lbs.
Description
The wielder can cast up to three spells per day as though using the Selective Spell feat. For each spell, he can select up to four creatures of his choice within the area that are unaffected.
Construction
Requirements Craft Rod, Selective Spell; Cost 1,500 gp (lesser), 5,500 gp (normal), 12,250 gp (greater)
A Wizard with the Fire school can remove squares from the area of effect of his/her fire spells. This ability doesn't kick in until level 8, though, so your party members will just have to stock up on fire resistance for three levels. It also has a limited number of uses. Still, you get it sooner than the metamagic feat suggested above, though a rod isn't too expensive.