Of course it's possible - there's special MPT player which allows you to play msx on 3 channels and one is left for sfx. This trick is used for example in Magic of Words game:

http://atari.online.pl/v01/index.phtml? … c_Of_Words

And in upcoming Galaxia ;)

Fast player is for normal usage, so it only can play one tune. It lacks the options the normal person doesn't use. It looks like you are not normal :D
You have the 2 solutions:
-analyze pla24s by yourself to find how to use it
-wait till I find the time to do it

P.S. Definitelly my page requires rework. New better layout and some more info would be appreciated. Also the .xex versions of old work and zips with the selfbuilding sources.

You are marketing manager???
Hm... it reminds me an acient joke about hunting elephants in Africa. The economist as I remember doesn't hunts elephants, but can give you a discount price for an elephant somebody else will hunt :D

O.K. I made a quick research and I've found that none of my MPT players have implemented triggering sound. CMC has, TMP has, MPT doesn't. Of course it is simple task to add this. But I'm a math professor type. I can prove that the hunting of elephants is possible and let the hunt as a exercise for my students.

P.S. If you really need that modified player I can prepare a special version of pla24d in a week or two.