How do I make an object with no clicktrough?

I have a problem in my project where there is Sprite1 stacked on top of Sprite2.

When I click on Sprite1, I add 1 to global Variable1.

When I click on Sprite2, I substract 1 from global Variable1.

Currently C3 registers both events and Variable1 results in 0, but it should be -1.

This works, thank you!

Now comes the question: If I have 100 items stacked, do I need to make this inverted condition for each one?

I suppose I could use a family, but managing it would be terrible.