Multiple shipments for Sales Orders

Fisherman

Our demand comes in daily quantities/sums, which we use to create Sales Orders, but we may create multiple shipments against a single sales order in the course of a day.

Our users would like the ability to create warehouse shipments in cube quantities so that they can drive/control the picks for a single truck. For example... given the following demands

Item 1 - 300
Item 2 - 400
Item 3 - 500

We would create a single sales order for today's requirements with 3 lines on it matching the quantities above.

The shipping supervisor might then decide to put 100 of Item 1, 200 of Item 2, and 200 of Item 3 to go on the first truck. They might repeat those quanties for Truck 2, and then ship a third, smaller truck for the remainder.

We know that we can set up a Warehouse Shipment and pick against it, register multiple times, and create multiple sales shipments representing the different quantities, but that still allows the picker to pick more than can physically fit on a truck. Is there any way to set up multiple warehouse shipments so that the picks are better controlled?

I've done some searching online and on these forums, but haven't turned up any good leads yet...