I was looking at doing this too but never managed to find a way, the only thing I found which helped in some instances was in the Object tab of the emitter, the ray visibility section allows you to tick or untick some options that could help depending on your materials.
I’m sure when I used Lightwave many years ago, it had all sorts of options for this too. You could turn off the reflections or light bounces from any object onto any other in the scene.