bracket, when there is only one instutment of a group?

I can’t find a way to get the following result:
I have a score with two solo insturments (no bracket) and two groups with a bracket. At the end of the piece, in one of the groups there is only one system left and the bracket goes away. I couldn’t find a way to keep the bracket without getting an extra bracket on the Solo instrument. Any suggestions?
I found an option to show also a bracket on a single staff, but than I also get brackets for the solo instuments. Perhaps there could be another option for the case, when there is only one staff of an otherwise grouped ensemble left.

Hopefully, the whole “Brace, Brackets and Labelling staff” areas will be revisited soon and improved at the top level! We’re confident it will meet all our needs then.

That’s what I hope, but I have a concert project soon and I would be great, if someone has got a workaround. I just didn’t look good at the moment and people got confused yesterday in the rehearsal.