How to overlay a material on top of another material?

I want to dynamically highlight a certain actor in my game. That could be any actor using any material. I would like to achieve this highlighting by adding a semi-transparent color to the existing actor material, so that one can see the original material through that colored semi-transparent “overlay”. (But I don’t want to modify all the existing materials to change them via parameters at runtime or something like that.)

Is there any way to achieve this, so to lay a material on top of another material? I tried to experiment with “Material overrides” of a static mesh in one of my actors, but that didn’t work out.