Just to clarufy my question, what I want to know is if there is a list of IPs, something like an asset group, of unscanable IPs. No matter who tries to scan those IPs, they will not be scanned.
There is an Host Exclude list that is subscription wide. An IP in that list will not be scanned.
You can access the list in the VM module by going to the Scan section and then the Setup tab. You'll see the option there for Excluded Hosts.