We are renting / type of containers and we need to be able to determine whether the container must be returned to the supplier when full containers are delivered.
So we gave one PO with 100 units of item ABC which are delivered in 1 container . If the container is full , the container must be returmed to the supplier so we need to be able to catch that information so we can send back the container t o the supplier.
For the same containers, we need to keep track also of the accumulated quantities and know when those containers should be return to the owner.
Off system would be my recommendation given cost and management. You could consider adding it as an item type. You could look at WMS and the containers and do it as a specific type but you dont mention WMS and that could be a big ask to implement just to track some containers.
As in add an item to physically track it, create one, then track it, control it as an inventory item. Complete pain, but it is an option.
The other way is try looking at container types and configuring your containers or license plates to segregate and then report on those rented ones that need to go back.