Exclude servers from SCCM updates

Hi there,

I've got SCCM2012 R2 and use it for OS updates. I'd like to use Window update only for certain servers (not SCCM) - the reason is they are in a cluster and I'd like to use Cluster Aware Updating from the microsoft windowsupdate site rather than from SCCM.

In WSUS I'd just apply the GPO where needed but how can it be done in SCCM?

I've created a Client setting in SCCM with Software Updates disabled and deployed it to my group of excluded servers. That removed the relevant actions in Configuration manager on these servers but it still keeps the registry entry HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Microsoft\Windows\WindowsUpdate\UseWUServer=1 and SCCM server IP is set up in Local Security Policy on the servers. If I change these registry and policy settings manually, they'll reappear after some time.

Any ideas?

Thanks