Migrate computers from AD Sync group to SEPM group

Hi

I need to migrate all the computers from a AD sync group to a new SEPM group.

I realise you could copy all the computers from AD sync group to the SEPM group, and then delete the AD sync group.

Would this be the best way to go about this?

I need to ensure that the computers do not change the policies by ending up in the default group during this operation or anytime in the future.

Thanks

DM