I suspect that you are right about the multiple teams. I also suspect that all teams were set to go at about the same time, but that somebody screwed up and didn't account for the different time zones across the country. That mistake saved those west of the Eastern Time Zone.
"...the different time zones across the country..." They had to know about the time zones, ata, but NOBODY read their pilots' manual, about the FAA ordering all planes to the ground in the event of attack.
BTW, a transponder setting of: 0-0-0-0 means 'Incoming Ballistic Missle', and triggers an automatic FAA response. Not stupid - just arrogant and clumsy, IMHO....FRegards