Link serum controller keyboard or velocity to master volume within serum

I wonder if you can link a controller such as Keyboard to the master volume for serum. It would be super useful. I could make the volume not get as loud on higher notes easier. I tried to link the note controller to OSC A Level and OSC B level but it can alter the sound to much were the master controller would just be changing the level of everything.

In Matrix, Source: Velo Dest: Global->Amp, and set the mod Type bi-directional.