I'm a newb playing on Age 2 and I can't find a topic on this.

Can you declare war and attack a city that is already colonized by another player?

If so, is the suzerain holding that city notifed that you are attacking?

Can the suzerain send troops or do anything to stop the attacks?

I'm assuming a the suzerain would consider attacking a colony an act of war and would probably fight pretty hard to protect their investment.