The spell Sam's talking about would be Hallow, though it would be very difficult to actually pull off and would require some considerable resources.  In the area, everyone would receive protection from evil (through the natural circle against evil) as well as one other spell effect.  I'd default to Death Ward.  However, it would be a Big Deal.  DC40, base.  Six checks, so pairing Guidance of the Avatar with Divine Insight isn't gonna cut it unless we get a<em>lot</em>more castings of those spells (Mark using lots of schema?).  The result would be a 40' radius zone for the effect (doubled for a +3 boost to the check), but if we can draw the zombies there, a lot of their stronger subspecies' best abilities would be negated, and it could stay up over the course of days.<br/><br/>Probably not worth it, but if we go with the zombie purgey ritual contingency, this can provide significant defense and really help secure the position.<br/><br/>Anyone got a Spellcraft check of +10 or better?  If so, you beat Sam and it'd free him/her up to pump you with skill-boosting buffs (Guidance of the Avatar).