Separate Emissive Texture Map from Albedo

It would be incredibly useful to separate the emissive texture input from the diffuse input. For example, consider a low poly background building that has a single Diffuse map for the windows & exterior. With a separate Emissive texture input, it could also have glowing interiors with controllable intensity.

As it stands now, we can either have a fully glowing building, no lights, or have to model a full building or separate interior layer. (There are similar situations which could benefit from a separate Metallic map as well.)