How to add a closing brace?

[Arjan Bos]

I'm writing some vocal music. I have three staves without connecting 
bars. I'd like to have a Start Brace, no connecting bars and an End 
Brace. The Start Brace and the disconnected bars are in the 
documentation.

 I do have them in a StaffGroup and I remove the "Span_bar_engraver". 
How do I add an end-brace?

I presume I'm not the only one who'd want this, but I didn't find it in 
the archives.

TIA,
Arjan

---
Look, that's why there's rules, understand? So that you think before 
you break 'em.

-- (Terry Pratchett, Thief of Time)