Seems to me I read that you could do that somewhere on here. I think you'd need a relay in each for (for that doors opporation) plus relays in the drivers door for each window. My moms 540i has the auto-up/auto down for all windows, I love it, just
and all the windows go down. It also has, where if you put the key in the door and turn it the opposite direction, all the windows lower and the moonroof opens. That's such a sweet car 
