To me (not very experienced in such things) that sounds really tricky. On a mac (I don’t know windows) you could use Applescript ([tap.applescript ] is the only thing I’ve used, but there are probably others) and/or using the [shell ] object (I think this executes terminal-like commands).

The only thing I can say with any certainty is that the standard max key objects won’t work when max is not the active application; you have to use the [hi ] object to detect keystrokes.

On mac it wouldn’t be too difficult to do what you need by executing Applecripts from max and changing the behaviour or your patch accordingly, opening and closing applications etc is very simple.

I think the main trouble you’ll run into is that you would have to do the whole thing in an entirely different way for windows and mac.