Thanks for asking, I had to do a bit of digging on this in order to give you an answer. A wide band O2 is essentially a 0-5 volt sensor, similar to a pressure transducer, with an additional wire for the heating element. On the Pro Dash, inputs 1-13 are capable of receiving a 5 volt sensor. I'd steal the sensor heat, 5 volt reference, and sensor ground connections from the main wide band on the Terminator X, and then wire the signal wire from the second O2 sensor to the Pro Dash. Once you have the sensor wired up, then I'd go to your laptop and configure the I/O ICF for your Terminator X and have it connect to the Pro Dash through the CANbus connection. Your Terminator X should be able to read your second wide band O2 now. You can find a step by step guide in pages 15-19 of the Pro Dash instruction manual.
