An Analog Multiplexer Circuit is often used when only one input channel is available, but several Sources have to be connected. (e.g. AD-Converter, DataLoggers etc)
For this purpose you might want to consider an AnalogMultiplexer circuit which can switch Signals very fast and with low distorion and high accuracy.
Here are some Links to MultiplexerCircuits
Here you may find Circuit, Basics, Schematic Diagram and DIY Kit components for Analog Multiplexer