Is there a list of zones where GMs can be spawned?

[ShardWarrior]

As the title suggests - back in the day on Triumph we used to have fun running multiple teams of Synapse or Crimson's arc to spawn multiple GMs at the same time.   I used to have a lot of fun spawning the Kronos Titan in King's Row as an event for our SG. 

 

I've run a few tests recently and it seems like the only place to do this is FF, PI or Skyway City.  I know Atlas was a zone where this wasn't allowed, however as I remember all other zones were open.  Is this still the case or are we restricted to where we can spawn the likes of Babbage and the Kronos Titan?  Is there a list anywhere that shows what zones are ok?

 

Thanks.