Hello esarmien,
the other solution that is probably more comfortable could be to disable each node for everybody:
/etc/NX/nxserver –ruleadd –class=node –type=<host>:<port> –value=no
and then enable node only for specific group:
/etc/NX/nxserver –ruleadd –class=node –type=<host>:<port> –value=yes –group=<group name>
We do not have –value=only available.