There certainly is Josh and you have a few options on how you can do this:
1. Buy the AS-SysLink cable. The GPS Receiver plugs into this cable and the other two ends of the cable plug into the COM port on each unit.
2. You can buy two of the AS-HHGPS cables, some connecting wire and use the NMEA Output from the 1198 to the 937c unit.
Of course if you already have the second GPS Receiver mounting it up front would be the cheapest and easiest way to get GPS on your 937c unit. It would also allow that unit to mark more accurate waypoints as well.