Feint makes them flat-footed against your next attack, so only that one would be a sneak attack (if you succeed in feinting).  Though with a free action feint, you could feint before each attack, though they'd get a Sense Motive+Base Attack Bonus against each one (-4 Bluff vs nonhumanoid, -8 vs animal intelligence, impossible vs nonintelligent [zombies and spiders]).