Creating a shift + knob to determine macro knobs and change its parameters with Beatstep Pro in Ableton

Hi, I just got myself an Arturia Beatstep Pro, and trying to do what the title says. I'm new to max / msp, but have learned some of the basic things in max msp.

Here is what I want to do and my problems:

Im trying to use the same 2 knob to control different macro in different channels, but my problem is that if i map it to ableton and try to move it, i'll end up affecting every channel. What I want is a way to just highlight one specific channel at a time.

I thought of using the step numbers in the step sequencer of the Beatstep PRO as a way to differentiate each channel. The step sequencer button seem to be a toggle that output a 127 when pressed and then immediately revert back to 0. I don't mind this but it seem to "reset" the values in my macro knob back to one.

I hope what I wanted to achieve make sense.
Can anyone please give me suggestion to help me build this thing? Other ways to achieve it are also welcome :)

Thank you so much! :)