Image Mask Effect

Again I must request help from the Construct-gods. I can never wrap my head around some effects.

What I'm looking to do is have two sprites layered on top of each other. The top-most sprite is semi transparent so you can see the sprite below it. The bottom sprite is bigger than the top sprite but I only want the part of the sprite that is underneath the top sprite to be shown.

I made an example cap to demonstrate: https://www.dropbox.com/s/yn8dr5ubs4lp3nf/image_effect_example.cap

I want the "eye pupil" sprite to only be visible underneath the "eye lens" piece. All the yellow part thats outside the "lens" should be invisible.

Is this possible? I feel like it should be but I dont know what combination of effects will do it. Thanks!

I think I've realized a way to do it, you can use layers for the eye pieces and the erase effect on a sprite outside of the lens which should erase the extra pupil from showing and show layers underneath. Hope that helps!