Counter with collision

fullviewmedia

this maybe a stupid question but, I want to count every time a actor collides with itself. There is an actor called yellow that gets spawned every few seconds, each time it collides with another of the same name the counter should go up by one, the issues is that as they are side by side they counter keeps going. Even with a flag to say start and stop counting does not seem to work as it is turned on again by another collision and counts all the yellow actors again which are side by side.