Firstly, we need two forces. Secondly, the unit's owner must be ally of an another player.
So I need something like Moba maps (such as DotA map).
Thanks for your help. With this system my map is almost ready for beta release.Why do the computer players need forces? You can have two forces for the human players and then change the owner of the units to an empty slot computer player. Also, you can set the ally with the trigger function "Player - Set Alliance".