Toon Shading in Blender 2.8 w/ Lighting Changes Affecting Objects

I’m doing toon shading in a scene using the Shader to RGB node. But I’d still like lighting color changes to affect objects in the scene, without having to go into each individual material and change it. I’m having trouble accomplishing this.
So for example, a red warning light is flashing in the room, and it should cast red light on all the objects in the room.