Servers visible accross multiple subnets

For security reasons, we would like it if users on one subnet cannot see servers on a second subnet when they browse network neighborhood.

We have a router between subnets A & B, however users on B can still see that there are servers on A(they can’t access them, they just see them). Users on A need access to resources on B. Users on B need nothing on A.

Any ideas to block or filter those servers from being seen?

Thanks in advance.

gruta@ctsi-usa.com