Anyway to buy airfare for myself and a second ticket with no name-I don't know who I want to take! yet!?

There is a really great airfare going on right now to the exact city during the exact time I wanted to go there. It's not til November, and I don't know who I want to take to this event yet, but I don't want to miss this great deal. Is there any way with any airline that I can purchase a second ticket with no name, but otherwise exactly the same. This is for a domestic flight. Then when I know I can add the name later? Why shouldn't you be able to buy two tickets in advance and not be able to provide the name on one of the tickets??