Specific Client-to-client configuration on a windows machine

[makkio]

Hi everyone.
I'm setting up a Windows-10 based openvpn server.
Basically it works (i'm not really new in this world) but now, what i want to do is to restrict access policies between clients, in a way that only some specific clients must have complete access to all clients, and some other must not.

I suppose i've to disable the "client-to-client" directive in server configuration, but i can't configure correct routes in the server.
I think it's something related to windows firewall on the server, but there's a way to configure it appropriately? Any ideas?
Thank you.