Try interfacing a 4051 analog multiplexer IC to the Arduino (which can switch one of eight signals); the Arduino alone won't be able to do it - see also:
http://www.arduino.cc/playground/Learning/4051
Try interfacing a 4051 analog multiplexer IC to the Arduino (which can switch one of eight signals); the Arduino alone won't be able to do it - see also:
http://www.arduino.cc/playground/Learning/4051