This was discussed here several times in the last year and I know that Dorico is set to draw barlines between the staves of groups (with the possible exception of vocal staves) and that this cannot be overridden, except by placing each instrument in its own group. Unfortunately, this prevents the left bracket(s) one would still want. I often prefer no barlines between staves, as they add to clutter, they can force elements to shift to accommodate them and they collide with hairpins. Has this behaviour changed in recent versions? If not, is it planned for a future update, hopefully the next one?
There haven’t been any changes to the way brackets, braces and barline groupings in either of the most recent updates, and nor is it something that will be included in the next update, I’m afraid. But we do of course plan to provide greater flexibility in this regard in the future. I hope you will understand that I cannot provide a firm guarantee of when we will manage to get this done.