Require to put items from different lots into single lot in same subinventory

Hello,

Scenario:-

Using Discrete Job we manufacture an Item which is Lot Controlled item. So when we do WIP Completion transaction we mention the lot number for the completed Item. In each lot we have around 100-150 max qty of items in the same sub inventory and we have many such lots having total on-hand quantity around 9000. During Sales order ship-confirm transaction we have to compulsorily enter a single Lot. The quantity to be shipped is 9000 but there is no single lot containing that much quantity, and due to some business compulsion or requirement the user doesn't want to split the sales order lines.