Musocity,
Thanks for honors, I will post that wish that you formulated well. But... there is more to that.
Chord Track was a good move by PGmusic, which btw was initiated by justanoldmuso, however it is missing couple of important pieces in my view.
If I am thinking it right it needs 3 items:

#1 What we discussed here on ignoring all "other" notes.
#2 Ability to create more chord tracks that will accept changes, without going into "generating a chord track" each time change is introduced.
#3 Possibility to create tracks with different specified ranges that will also accept changes automatically / simultaneously with tracks with other set ranges.

Simple example:

NI Session Guitar + Synthmaster in BIAB.