The current options are to filter by a disk's SCSI address, datastore name, VMDK name (can use wildcards if needed), or hard disk number. So if you put one of these VMs in a subclient on its own and you know all of the disk numbers of the disks you would like to backup, you could set a filter to not backup any other disk numbers. That would filter out any newly added disks by default.
Another option would be to set the newly created disks in VMware to be independent disks. Those disks would not be affected by VMware snapshot operations and subsequently would not be backed up. That would require someone to set the new disks as independent disks when they are added, however.
If you could give us some details of what you are trying to accomplish here that might help us figure out how we can do what you are trying to accomplish. Or, if you have a way of accomplishing this already in mind, we might be able to see if there is a good option in CommVault or if we need to request an enhancement.