Override Material Emissive Property


I would like to know if it is possible to instance Materials and then override the emissive ?
I need to create some sort of color masks with the characters in my scene but I need to keep the influence from the other properties (opacity, world offset etc) thats why I want to do that.

One of my lead was to add a color parameter value procedurally for each of the material in the scene, that connects to the Emissive property, and then create dynamic instanced shader with a new emissive color … But I’m not sure at all about this.