It's simple; there are 5 teams. The event has a scenario that needs to be accomplished, and it's 3 zombie teams vs 1, with the 5th team being on break and generally hanging out at the halloween pizza party.
I wrote a huge 5 page document about it.... gosh almost 7 years ago and it got approval by a couple of fields, however nothing came of it. Essentially, it's a mag-fed (max 30rnds) low chrono game of flag football. Players had points that they distributed on their loadout, (pistols cost less points than tippmans with the 30 rnd hopper cap. There were things like paint grenades, lives, etc). Zombies never contact players directly, they only grab flags. It made for some really intense fun.
Hopefully the business will pick up soon so I can devote all my time to this.