proper formatting for verse segments (e.g., 1a, 1b, 1c, etc.)

Question

I'm looking for help with the proper formatting for verse segments (e.g., 1a, 1b, 1c, etc.) in Paratext. I'm working on modules that require them. Ideally, PTXprint will also recognise them.

So far I have filled in 'Verse segment characters' in 'Other Characters' of 'Language Settings' in Paratext, but I don't know where to go from there... There's nothing I can find in the USFM 3.0.0 documentation. I found "How do I implement a custom versification for my project?" in Help, but it didn't help me much. If you have any advice / tips, I'm all ears! Thanks,

Paul