Cel Shaded Lights

I have a Post Process Cel Shader Material that creates a basic cell shaded look.

If a colored spot light shines on an object it changes the shader to lighten the area but it doesnt show the color of the light on the object.

I want to have the area with the color of the light added without a gradient and has a solid separation between the colors. The Stylized Rendering System on the UE marketplace has a tutorial video that shows it can do this but i would like to learn how to do this without buying the pack.

Stylized Rendering System: https://www.unrealengine.com/marketplace/en-US/product/stylized-rendering-system-cel-shader
SRS Solid Lights Tutorial: https://youtu.be/--gpOVDh0yk

If anyone has tips or knows how to achieve this i would appreciate any help. Thanks!