Compare two element of the same kind

Hi I have the following event:

Enemy On collision with Enemy.

and the action should do something, like have the first Enemy turn right, and the second turn left (in this example, when enemies collide, they change direction).

My question is, how do I reference the first enemy and/or the second, in the action "code"?

You could look at addressing their instance IDs (Enemy.IID) and tell the one with the smaller ID to flip 180, and the one with the bigger one to flip 180 as well, perhaps.