Alright if you ever played NS then you know where i am coming from. This idea is just like the ns_siege maps (just making more chooices). The "time" consuming paint shop I did will help iillustrate my thoughts. The doors I pointed out are on time delays; the first one opens in 2-3minutes, and the second one opens in 15-20 minutes. Also there should be ceilling talk enough where people can not shoot artillery over the walls. Basiclly a big box. Also, I do know you can restrict research to a individal side. What would work out great is if you can place atrillery inside the artil. And once the artil door opens artillery reseach can be started on the NF side(more like a time delayed event). NO belly-aching about how this is like money, when it is not!
I really liked siege maps, and I think this sort of map would be a nice addition to the game. However, I'm certain you could not build a map such as that with the current entities, so it would require a bit of work from the devs... Alternatively, this may be posible with a server plugin, although I'm not sure whether it'd be practical.