They are part of a device group, they could be clone targets or “reserved” devices for something your symm admin is doing.
I ran the symdev -noport -nobcv command and found I had other hypers defined at 27.887 or 27887 MB. They look like are free, however, I noticed some of the hypers have a grp'd attribute. I really do not want to cause any issues while the dmx primary admin is gone on vacatoin and so can anyone tell me what that attribute is about?  Thanks in advance!  Benita 
symdev and grp'd and no/grp'd