Please HELP!

Problem: Currently, we can't allocate sales orders at a detailed level according to "unit of measure". At one point in a selling season we have sales orders for items that ship parcel (eaches) & those same items also ship LTL/ Full truckload (case-packs& pallets) Those items are being detail allocated from the same area in our warehouse with the same unit of measure (eaches). As of now, we buy, sell, and store all in eaches.

Future State: Sales orders can be allocated at a case-pack level (qty. of 6) & a eaches (qty. of 5 or less) level from two different areas of the warehouse.

Does anyone have any experience with this problem or can direct me?