I have a 798c si unit at the console with a gr50 receiver installed near the transom. I have a 788c unit on the bow with another gr50 receiver installed nearby. I have an Interlink unit installed under the console. What is the best way to connect these units so each of the depth finders will see their respective gps receiver and the two units will trade waypoints, routes, etc? Also any part numbers of extra cables would be appreciated. Also any advice on the setting of the "GPS Receiver Override" menu on each of the units would be appreciated.