Many carriers have reservation systems now through which we can share our information and have seamless travel for parcels and passengers, but we need a communication platform. Yes, for sure, if you're going to do any form of interlining, you need a communication system for all carriers.
We used to be with Greyhound in Orleans at midnight, trying to find out if we had enough seats for passengers travelling from Ontario into Quebec and the Maritimes. We had a manual system, but we did it for seamless travel.