How can I control my A/C room by room? ?

I have a large two story home with 2 seperate 5 ton units. I want to me able to shut down the registers throughout the house at night and leave only the master bedroom active with a secondary thermostat in the bedroom. I may want to isolate one more room.How can I control my A/C room by room? ?
Basically look up your A/C manual (if you have lost it then go onto the internet and download the manual) and look at how to isolate rooms! Then after you have isolated the rooms u should be able to set a temperature so that when the room drops below or exceeds that temperature, the A/C automatically kick it and warm it back to that temperature!