Help in Delivery and Pickup

Hot to assign the following relations?

  • Pickup+Delivery:- Here the vehicle will pick up something during the trip after leaving the warehouse and will deliver the same to some location before returning back. Here Nothing will be loaded at or brought back to the warehouse.
  • Delivery+Pickup:- Here the vehicle will deliver something at a location that was loaded into it before the trip started and will pick up some other things from the same location that will be brought back to the warehouse.

Have you tried using shipments?

Yeah but with what arguments?
I have different delivery and pickup sizes but shipment has only one size.