Would killing the original attacker "break the spell"? In other words, would the zombie vampires be released to either a) die or b) return to previous form? If so, would probably need to boost vampire's hp, but maybe not.
This would, no doubt, make coding for some ridiculous coding (I honestly have no idea) but would play to the theatrical vampire portrayals--killing the "queen vampire" (or whatever they're called) to release your loved ones, etc.
