@basherstech It might be easier to use firewall rules to allow the PCI network access out. That is a separate network or VLAN? Though, you'd have to maintain a list of the Windows Update IPs which could be a challenge. One could find and allow all Microsoft IPs by ASN number in pfBlocker.
Many, many years ago we did something similar but it was not for PCI so wasn't on a separate network, and was on a Windows Server network. The client just wanted to prevent certain PCs from web surfing. I tried to look it up but don't have that info anymore. I think it had to do with Conditional Forwarding which is a feature on Windows DNS. But, if you set up your own DNS server on the PCI network you might be able to forward only certain domains and not resolve the rest of the world?
One other thought, there is a "Python Group Policy" feature which is named poorly but it will "bypass DNSBL for the defined LAN IPs." Possibly, use a service like CloudFlare family DNS to block adult content via forwarding, block all domains in DNSBL, and set everything on LAN to bypass DNSBL? So the PCs on LAN would get forwarded to CloudFlare. In other words, block *.com but add microsoft.com to the DNSBL Whitelist section.
Sorry for the vague answer, maybe it helps.