The combination of the info Muzic Trax above with the PSRUTI can be made to work. PSRUTI has an analysis function that determines what the chords of the MIDI file are. Since I can now have them come across in a single MIDI channel it is easy to help it find them and then produce the special chord events that the Yamaha keyboards and other Yamaha instruments use. The files seem to be "standard" MIDI and you load them onto the device using the Yamaha SoundFiler utility.

The only thing to remember is that you may want to strip out the MIDI chord channel before saving the final MIDI file or it might get "played" by the device. Muzic Trax want this, but my purpose is to get the chords to be displayed by the device in much the same way it would display lyrics for you to sing along to, but not to actually play the chords.

I am not completely done with the procedure yet, but the mechanics of this seem to work.