The 'Add object to target' action is not 'personal'. It does not add 'picked' targets. It adds objects and their instances to its 'auto' target system. All instances of that object. Also, once added, the instance is not a target yet. It becomes a target when it comes into range.
You can override the 'auto target' system by using the action 'Acquire target'. This makes a picked instance into a target (when it is in range at the moment the action is called).
The 'Add object to target' action is typical used once and under a 'on startup' event.
If you divide them in teams by instance variables, the best is to act on the moment that an instance becomes a target. (i think).
Condition > On target acquired
___ Sub Condition > target does belong to team ?
______action > Unacquire target