TRACK 05 AUDIO ISRC USMR17500048 INDEX 00 12:28:60FILE "05-Rush-The Fountain of Lamneth: I. In the Valley - II. Didacts and Narpets - III. No One at the Bridge - IV. Panacea - V. Bacchus Plateau - VI. The Fountain.wav" WAVE INDEX 01 00:00:00 INDEX 02 -21:13:07 INDEX 03 -20:15:09 INDEX 04 -16:34:22 INDEX 05 -13:49:59 INDEX 06 -9:03:29
TITLE=The Fountain of LamnethTRACK PART=00:00:00|I. In the ValleyTRACK PART=-21:13:07|II. Didacts and Narpetsetc.
I think the biggest roadblock to this is finding someone who wants to develop a component capable of doing what OP wants. It basically boils down to a chapter index that only the component would see and which would be displayed using a custom tag.
If there's a consistent format (cuesheet, tags) in which the information about track parts is present, it would be possible to write a custom WSH Panel Mod script that could display the current "subtrack title".