You hit the home button and reconnet the Wiiremotes, then power on the ones you want to be 1, 2, 3, 4 in the correct order. Either that or you power down the console and turn turn it on and power the remotes on in the order you want them to be.
I've had problems when bringing my wiimotes over to a friend's house and connecting to thier wii. Mine are usually set for 1st or 2nd, but when becoming 3rd or 4th, I ran into a problem. I just followed Nintendo's directions of opening up the battery cover and pressing the red button as I pressed the red button under the SD slot and everything worked out fine. (Bit of a pain to remove the battery cover when you've got the Wii Condom on though)
