Custom bracket design?

Does anyone happen to have an idea for a possible workaround to imitate this “double bracket” which joins the vocal staves in the BGA editions?

No, I’m afraid I can’t think of a good way of achieving this in Dorico directly. You could do it in a graphics program after completing the project, perhaps.

Thank you, Daniel! Maybe if once you implement the feature of changing the design of individual barlines (I’ve just read that it was requested in another thread), that could be a workaround for doing this by changing the design of the systemic barline and just keeping the default bracketing settings.