I don't know about the "triggering a new song" but i did my arrangements all in OGG. Took the music I wanted in-game, put on Audacity, cutted where the loop will start and when saving, where you get to write down the artist, track, album, track number and so on... I created two more lines. One called LOOPSTART (writing down the SAMPLE time of when the loop starts) and LOOPLENGTH (writing down the SAMPLE time of the length the loop take to go back to the LOOPSTART).
All my new OGG musics works fine doing this way.
Example:
The music has 1.000.000 SAMPLE time, and I want it to repeat from 200.000 to 900.000 and keep repeating.
Then the LOOPSTART is 200.000, and LOOPLENGTH is 700.000