Shipment creation in ECC based on FO in TM

Dear Gurus,

We have a client requirement where we need to create Shipment (VT01) in ECC based on FO in TM using the standard scenario TM_ERPShipmentintegration_Out

If the Freight Order is for a Milk-run wuth different stages, such as, A-> B -> C-> D, then will these different stages be automatically reflected by the interface in the Stage of the Shipment in ECC ? We know that Shipment creation requires a Route master data in ECC. If we create the Shipment via TM interface, do we still need to maintain a Route A-> D in ECC ? How will ECC identify this Route ? How would it work if it is a round trip such as A-> B -> C -> D -> A

Thank you very much for your insights

Regards