How to light up selected track button RELATIVE to session box (on APC40 MK2 alternate mode)

Hi, I’m trying to recreate the APC40 MK2 behavior where the button for the currently selected track lights up, but relative to the session box — not based on absolute track number. Also, it works regardless on how the track is selected (via APC, mouse, whatever)

So for instance, if my box is placed on tracks B C D E F G H I and I select track C, it’s the SECOND track of the red box, so the SECOND button should have the light. If I move the session box or select another track, the light moves accordingly ot always signal “this is the Nth track of the session box that is currently selected” as button Nth as light.

If I use highlight navigation by attributing button to track higlighting, there is some automatic lighting but it is not correct (it always illuminates the 3rd button when C track C is selected because C is considered the 3rd track in absolute order – regardless of where the session box is its always the 3rd buttton that lights up)

Any clue on how to emulate the original behavior?

Thanks for the help !