I am trying to control the amount glossyness/specular (not roughness) of glass but not able to find any option in cycles. I have tried both the traditional glass shader and the new Principled BSDF shader - none of these seems to let you control the amount of reflection on glass.
I understand that it might not be physically accurate but is there a way to do it?
Here is the blender scene in case anyone wants to examine the setup. http://pasteall.org/blend/index.php?id=47771