did this with 93 lvl Necro with Healer Merc, 93 lvl Cleric with Tank Merc, 90 lvl Rng, and 90 lvl Wiz.
Placed every one but Necro in room one, and had Cleric start event.
Necro with pet on greater hold and healer set to passive, pulls mobs from room three and two to room one. Once there reset healer to reactive and took pet off hold, casted only swarms and AA pets.
Rng did autofire with bow as targets swarmed Merc Tank. Wizz cast DD on targets, while Cleric spammed heals on tank.
Villagers spawn in room one so AEs not wise to use.