Maybe use some sort of hive as spawn points for zombies?

[AtomSplinter]

@Yarrrr

Spawner

Bulging mutant growth that constantly spawns minions to spread the infection.

• High health and are immobile
• Has no form of combat/self defense
• Spawns walkers or lurkers up to 5 active when close. Can spawn Stumblers indefinitely
• Has small resistance to most damage sources except fire and explosives

@GreatHeroJ maybe he meant something like this (also discussed before).