A batch file is what I'm planning to do. But I haven't looked into the details. But since you asked I looked again at Sharp_1's help pages. He has the Sony 777 DVD changer. Which happens to have a serial port, and can be controlled from the command line as well. Here's his page describing that technique;
http://xlobby.help.googlepages.com/dvp- ... angersetupSo looking at it I suspect something very similar could be setup that uses the Mediachanger.exe instead of the sony_cx777es.exe that is used in that example.
Hopefully after the first of the year, I'll get a chance to get mine setup.
Aaron