Yeah, so like Final Fantasy XIV's fate system, or Destiny's public events. There could be a tall office building overrun with Plague Hearts, and you and all the groups nearby team up to destroy them before it spreads, or the longer it's up, the more zombies that spawn, incentivizing players to work together quickly to clear the building. Rewards based on amount/time of participation, kills/damage dealt, etc. In SoD2, Plague Hearts take over a single floor garage or house or something. Imagine a parking deck or skyscraper, going up floor after floor with other groups to take them out as quickly as possible, before surviving gets even tougher. I'm over here sweating from my own idea lmao. Can't wait to see what UL is cooking up.