Hi everyone,
I'm encountering the exact same problem, although with a different storage vendor. I have three Shelves of Dell EqualLogic PS6500's that I'm encountering the issue with.
initially, when setting up and configuring SRM I didn't have a problem with the initial 2 VM's that I created for testing. However, as I created more VM's and presented them for use and moved forward in creating new protection groups to test staging of systems during a real DR recovery incident, the Volumes began to become grouped together, not allowing me to individually select them for creation of the Protection Groups. I've gone through the trouble of disassociating the VM from any connections either to the Host or to another Volume, and even deleted everything and started from scratch, from the volume all the way up to the VM. Any direction in which way to proceed would be most helpful.