I looked again at the BibX example for partdesc (which is where my
partDesc came from).
Would this -- the ability to have composite references (the specific
details of how to name elements is less important) --not better
accommodate your example Suzanne?
This was designed to be able to get a citation like:
Some Collection Title, volume 3, parts 1, 3.
The other example was...
Some Book Title, chapters 1, 3-5.
BibX, BTW, parses all start/end extents, including page numbers
(important for formatting processing).
The above doesn't solve your interest in including titles of course.