Hello,
This topic is of particular interest to me. Using the proof-of-concept code Thomas Morley provided, I've arrived at the attached pdf. The results aren't quite what I'm aiming for, but it's close.
Some features I'd like:
1. the option to have all brackets horizontally aligned
2. closer to the left page margin (as opposed to moving the margin itself)
3. I don't know why my ChoirStaff names are on the right of the brackets, but I'd like them on the left instead
A dedicated StaffGroup/ChoirStaff name engraver would make engraving polychoral works a much nicer experience. I'm glad this possibility is getting some air time.
Thank you.