If you have 6 1 pole Breakers you should have 6 circuits. I take it you have a gas stove and no dryer? I am not familar with NYC and the way they do things so I dont want to get you in a heap of trouble. If you have your own meter and pay the electric I would shut off all breakers you cant find and see if any neighbors complain. Make sure you are not shutting down and fire alarm eq. These should not be on their own circuit but who knows what they did.