I had a DL flight booked for me by an organization for as part of a group of 25 or so.

After I got my individual 006 stock ticket (booked as a T fare)and added it to my trips, it said not upgrade eligible for all segments. After contacting the organizer, who asked the travel agent, who indicated no group tickets are upgrade eligible.

That sounds strange to me, but plausible. Any other data points out there?