Post Process Only Visible Behind Object?

I have a character with glasses, and I’d like to have anything behind the lenses of her glasses set to unlit, so it’s just their base color with no lighting effects applied to give it a cartoony effect. Right now that area of her skin is set to be emissive, but I don’t really like this solution as it lights everything around it, and the effect is broken if you view it at a low angle

I downloaded this post process effect but I only understand how to apply it to a post process volume that affects things inside of the volume

I think the solution is post process materials, but I don’t understand them that well. The lenses of the glasses have their own material, so I feel like I have the pieces to make this work. I would really appreciate any assistance