How to allow a subset intranet as trusted

I just installed the latest v3. I would like to allows a subset of intranet computers into the Trusted Zone to share my files and printers. How can I do this?

I have tried, making a Network Zone with subset of IPs (say 192.168.0.1 to 192.168.0.18) and then made this as trusted zone via Stealth Option. But this allows all other users on the intranet to access by files…

What am I doing wrong? Do I have to specifically block all the other computers for this to work???

Are you using 3.0.25? There have been reports of network zone rules problems, as in https://forums.comodo.com/help_for_v3/my_network_zones_wont_remember_settings_cfp_3025378-t23800.0.html . Do your settings still stick after a reboot? You may need to revert to 3.0.24 for now. You can get it at Download Comodo Internet Security 12.2.4.8032 for Windows - Filehippo.com .

Here is what I did to make the settings stick.
Added settings/rules → Applied Them → Shut Down CFP → Restart CFP (without rebooting)