"Pairing" two instances of an object

I want to be able to "pair" two separate objects, when there are several of each object.

For example: I want a green square to set it's position to a red square every tick, but there are multiple red and green squares. Each red and green square needs a partner.

DualInstancePinning.capx

This was actually a bit harder than I expected (pinning two instances of the same object together), but if you use the Pin behaviour and an invisible helper sprite, it can be done quite easily.

If the two objects are actually different objects, just Pin one to the other.

might also be worth looking at containers