As popular culture has been saturated with zombies in recent years, I've gotten at least half a dozen ideas for zombie RPG campaigns. The main difficulty with using well-known systems for these, however, is that most RPGs emphasize combat against individuals, not against hordes.
I want to find a system that provides rules for battling and wading through hordes of zombies. More than anything, it should not force me to handle each and every zombie individually, because that will require too much time and effort when hordes grow large.
That being said, I'm not looking for rules on "mass combat" in general, because zombie scenarios are about a small group of people fighting an enormous horde, not about two armies meeting in a pitched battle.
Which systems can emulate battles against zombie hordes?
Note: I know there's a question about zombie systems in general, but the two of those that I have checked out don't seem to provide specific rules for zombie hordes, so that's why I'm asking this more specific question.