Hello Ed,
As far as G/C, I have some pistons with dual (independent N/O contacts), so one set would cancel H/W and the other something else. Altho I wasn't exactly thinking in terms of an external, independent system, but rather something that could be done within Hauptwerk as a possible enhancement.
We definitely wouldn't want to implement anything within Hauptwerk that required or relied upon custom non-standard wiring of MIDI hardware. If we do implement functionality in Hauptwerk we want to try to make sure it's available and understandable equally to all Hauptwerk users, and works fully with standard MIDI hardware.
We can't change in Hauptwerk the way that sample sets' divisional pistons worked, since that functionality is 'wired' virtually into a sample set and there is no way that's reliable in general that we can 'unwire' that virtual wiring in order to change it.
However, if there's a genuine desire amongst users for lighted divisional pistons for all sample sets then we could perhaps consider adding some kind of option or options for the master scoped pistons to light up, perhaps in mutually-exclusive groups according to their prefix letters (A1, ..., A10, etc.) or globally. Of course the risk there is that it might create some confusion since their scopes are entirely user-defined, and not necessarily grouped into non-overlapping subsets (e.g. divisions) by prefix letter.
We'll discuss that here to see if that's something that we think would be desirable for the longer term.
Is that (an option for master scoped pistons to light up within mutually-exclusive groups by letter prefix) something that other people think would be beneficial?
The sample set we are using is the MDA Skinner. Pretty sure Brett has more important things to do aside from making an option of possible lighted pistons available for a limited user base, hence looking what else could be done.
Adding new functionality to Hauptwerk itself (and subsequently documenting, maintaining and supporting it) takes work too, but we'll certainly discuss and consider it.
Best regards, Martin.
Hauptwerk software designer/developer, Milan Digital Audio.