Not really. It really depends on what all scenarios you want to address. If you looking at a pricing point of view, you can price all the segments independently and then have a reduced rate if there are connections.
You can always change your itin to A-D and still have C-B valid with the 'arrival' to C unknown (in other words the passenger walked, drove, flew some other airline) from D to C.
Consider a real life example of inter-island flights or changing between LGA, JFK, EWR gateways.