Access rules. Permissions

Hello, I’m going to start working with Zero Tier, I like the tool, I need to be able to do the following.
I have a network with 3 devices, A which would be a server and B and C which would be clients. I need to be able to configure that A can be accessed from B and C, but that B and C cannot be accessed from any node. It’s possible?
Thank you

Yes, possible. See Im stuck using tags