Hehe, I couldn’t resist a little coding exercise: why don’t you download this and give it a try?
It’s just a simple tool that allows you to execute programs on receiving a (banked) program change, with a parameter that lets you insert the program number (e.g. “score_%p.pdf” expands to “score_123.pdf”). It also gives you the option to close the previously opened window before opening a new one.
Still very rough around the edges, but for your purposes, it should do the trick! And did I mention it’s free?
Cheers,
Torsten