Well, what about Edge? Willpower+Edge is a pretty good pool. In a ditch, the whole party can go for it, and drive away, or even (with a bit of luck on the rolls) disrupt the spirit. Even a powerfull (high-Force) spirit will think twice, when he gets hurt by mere humans. And it's an Attack of Will, so if the PC's are determined, they can win.
Especially, when their characters know it can work.