Custom Midi Relative Mapping

I was looking around for mixers with motorized Faders and everything is way out of my price range so my plan is just to make my midi controller. My plan is to have relativized mapping of the mixer channels so basically if I click on a sound sample which by default it automatically goes to the correct mixer channer for that sample. The midi controller will then receive an input from Fl studio and it will change the Fader position to whatever the Fader reads in fl studio. So basically as I move from channel to channel the motorized fader I have will change correspondingly and I can make changes to the sample from my motorized Fader. This way I don't have it linked specifically to one channel but whatever channel is in focus. I hope to expand this functionality to panning, mute and stereo seperation later on. Has anyone does this before or know of how to do it?