Get instance's angle from another instance?

Is there a way to get object's angle from another? I need this to make a system that could push overlapping objects away from each other. Tried using the "angle" expression, but it can't seem to get coordinates from two of same object. For example my object is called Enemy_Hitbox, so the command would be: angle(Enemy_Hitbox.X, Enemy_Hitbox.Y, Enemy_Hitbox.X, Enemy_Hitbox.Y,)

Since both of the objects overlap each other, the command gets only one angle and then pushes both of them into same direction and that's not what I want.

You can index objects. This is a bit easier with Families.

Hmm. I'm using a ton of enemies that are all supposed to repel each other. How can I make this work with more than one UID?