In a quadrophonic stereo system, 4 microphones labeled LF (left front), LR(left rear), RF(right front), and RR (right rear) are employed, and the receiver has 4 corresponding speakers positioned around the listener. It is possible to encode this information using the allowed 75 kHz composite baseband bandwidth so that a conventional FM stereo radio or television will behave properly, while a set equipped with 4 speakers will be able to direct the 4 microphone signals to the respective speakers. How can this be accomplished? (Note that this is a tricky question, and partial credit will flow freely.)