I thought the marines were placed dead in a fixed position on the ground, and the spartans are placed alive but with zero health so they fall? I'm probably wrong though, it's just what I got out of your other post.
In ODST, you could zombify with a small amount of grenades. With four players, 8 grenades could lift spartans or marines. Player 1 kills all other players above a marine, then throws well placed grenades.
But Imppa says you can respawn. Once Imppa gets proof, re spawning may be our new course of action for this.