Can't adjust planar reflection intensity

I am trying to boost the intensity of my planar reflections, but unlike in box or sphere reflection captures, planar doesn’t seem to have a “Brightness” parameter.

I have tried modifying the surface’s material to make it more reflective, but that alone is not enough.
I have also tried using a sky light for the same purpose, but that would make the whole level too bright.
I guess I would need direct control over the captured reflection texture (like a regular render target), so that I can multiply it by say, 3, before it gets blended with the rest of the frame.

Is there any way to achieve this?

Thank you.