Ok not quite what I wanted. I guess that the multiple starts in the fiction section are all player controlled then.
What I was hoping to do would have multiple computer controlled conventional empires but looks like not possible.
Yes pretty much all of the single system multi-Empire AARs are player controlled NPRs, just with good roleplaying.
IIRC there were a few attempts to do Computer contolled NPR multi-Empire starts, which very often degenerated very quickly into Armageddon scenarios as the individual Empires kept seeing enemy ships in "their" home system, resulting in rapidly deteriorating diplomatic relations and all out war. In theory it is possible to configure the starting relationships in such a way that this does not happen but I've yet to see anyone post that they have sucessfully managed it. I rather suspect that you would need either the developer password (which I don't have - see Steve W) so you could change the status of the computer controlled race or to manipulate the tables directly in the back end (which is rather risky even if you think you know what you're doing - not recommended).
Also I believe that the AI for CONVENTIONAL races is fairly limited (it certainly used to be) as the Non-TN start was a later development in the game (largely due to the historical influence from Starfire Assistant, where pre Tech Level 1 races were essentially cash grabs and therefore did not need a lot of AI). I don't think that its possible (in the Aurora application) for Computer Controlled Non-TN races to develop TN tech.