I presume you dont have acces to famelies.
Allow me to offer you 2 warnings.
1/ I am not an expert.
2/ I am pretty sure that there is no easy solution.
Two more general things.
On Collision is a trigger. In your Cap none of the 'sprites' is moving. So its kinda useless to use On Collision. The trigger keeps firing.
Because the trigger keeps firing, your Cap is in a state of an endless loop. You should be more carefull with that.
Now. Your problem. Why is it not that easy?
Well, when using 'on collision' condition on all those 'sprites' a big list of sprites is returned as a result in the Selected Object List (official term, wich i call 'the picklist'). 15 in your case.
On top, you want to compare them in pairs.
Is one's flag 0 and the other one's flag 1, then do this(), if they overlap.
This Cap is one way to do it. The ListObject gives inside on whats happening. Lists are awsome debugging helpers.
You will see 'pick all' conditions.
The conditions before those 'pick all' conditions narrowed down The Picklist.
The 'sprite' that needed to be tested was not any more in The Picklist.
Therfore, enlarge The Picklist was needed.