If you look at the demo sketch on
http://www.arduino.cc/playground/Main/CapSense you will see that it describes the circuit for a single send pin and multiple receive pins:
CapSense cs_4_2 = CapSense(4,2); // 10 megohm resistor between pins 4 & 2, pin 2 is sensor pin, add wire, foil
CapSense cs_4_5 = CapSense(4,5); // 10 megohm resistor between pins 4 & 6, pin 6 is sensor pin, add wire, foil
CapSense cs_4_8 = CapSense(4,8); // 10 megohm resistor between pins 4 & 8, pin 8 is sensor pin, add wire, foil
One resistor per sense pin.