Hide object behind another object

Hello,
So i have an AR app that I use to load glasses on the face. What I want to to hide the part of the glasses that should not be visible. I have a head prefab and I want to apply a shader to that so that part of glasses behind it or covered by it would be invisible. I've seen videos where people apply a shader to a material that makes the head prefab invisible and any part of the glasses "behind it" is invisible as well (like an invisible wall). I have no idea or experience on shaders so any help would be appreciated!
Thanks!