Cel-Shading Question

I’m trying to mimic the look of Wolf Among Us inside Ue4. Currently in my scene I hacked together a simple line draw on the outside of objects combined with a cel-shader. Both are done in a post process material. Has anyone come up with a way to do the white outline effect in shadows only, (excluding lights), that’s not done globally. The white outlines break the effect when light is applied. I have included a picture of my scene and a reference picture from the game as well.