To second and add to what cjscol said, what defines a protection group in SRM is a replicated LUN or consistency group (group of LUNs replicated together). If you add a LUN or consistency group to an SRM protection group, all of the VMs on that LUN or consistency group have to be protected by SRM, and all of the disks for all of those VMs need to be located on that LUN or consistency group.
When using array based replication (like RecoverPoint) it isn't possible to protect some VMs on a LUN and not others. This has never been an option with SRM. If you want VM level granularity you would need to use vSphere replication, or place 1 VM per LUN.