Okay this is a good idea, its going to be a combination of a Team Defense map and a Individual Defense map. Each human player (defenders) has their own island. And then the computers (enemies) are in dropships, the dropships start by letting enemy forces out at the begining of the first island, that player is defending, then if/when the enemy forces reach the other side of the island, the dropship will pick the survivors up and drop them off at the begining of the next island. Then so on and so forth, until/if they make it past the last person's island.
INDIVIDUAL ISLAND DEFENSE
Same thing except your on your own, different islands, the last player alive wins, there is a dropship for every player, and if the enemy forces that come out of that dropship make it to the end of that players island, that player loses (end scenario in defeat or watch other players until its over).
None.