Wow so what you want is to make it so to attack a Npc it will cost you 2-3 times more troops BUT they dont regen rescorses for 6 hours.....

Well then if that happens You wont be able to do anything as u wont be able to Feed the army you need to take it But u will have to take it to feed them and if u do u wont be able to do it again for 6 hours and you will starve.

I realy dont think you have thought this through and if u have then you must be someone that has bottemless poeckets.