After a nasty Trojan virus, we have implemented windows firewall SMB block rules on our client computers to block incoming SMB.   This allows us to protect computers on the same network from a lot of malware file dropping.

We are also implementing a new Patch Manager that uses WSUS as an intermediary.   This mechanism requires SMB and WMI.   So, with Group Policy I tried to put in an exception in the rules using an allow if secure, then putting in the computers that need access.  I found out that if there are local rules that allow SMB and they are merged, it will allow anything through.   I also went the route of setting up a machine (windows 10) firewall manually, then exporting all the firewall rules with an exception (defined in remote computer scope), then denying local firewall rules and local security connections through the GPO.   This, initially, I thought worked.   However, when testing the same GPO on a windows 7 machine, it did not clear out the local firewall rules.

Is there something different I need to do for windows 7 firewall, or is there another route we should take?   Right now our LAN to LAN segments are protected with firewall, but clients on the same segment are vulnerable to each other unless I do a block rule (which takes precedent over any allow rule).