yepn indeed, we call it private sharding or private consensus. Far on the roadmap (4 months), but nevertheless, the team is thinking about it. You could also include or exclude some Geographics for ex if you don't trust a country or have a private consensus between only your own machine. If you are, say Morgan Stanley, you may be attacked only you by some machines and the crowd wouldn't know. But all your servers teaming together will see it.