A thought about changing tyre pressures.

Hey guys, I had a brainwave the other day and was wondering if it has perhaps already been done or maybe just cannot be. So here goes...

Even a newbie like me knows that different terrains require different tyre pressures. Lets call the max you want it 48psi and the min is maybe 12psi. My idea is kind of like fitting an air tight area that is connected to each rim that is openable and closable depending on what pressures you want the tyres at. So if you had the tyres at 48psi and wanted 36psi, you could turn it down from inside the car (like on the dials at the servo automatice air pressure thingos).

Could that work?

Cheers, Anand.

P.s. And no im not lazy... just innovative. :P