Item Master - Multiple Purchasing Category Assignment

Summary:

I want to be able to assign multiple Purchasing categories to the same item so that I can select these items within Self Service Procurement.

Content (required):

My client has many uniform BOMs where a common item is contained on Multiple uniform BOM's for various ranks. I want to create a Uniform BOM per Rank..assign a rank Purchasing Category against the item and then be able to search for this 'Uniform Rank BOM' category within SSP which will return all items contained on this BOM and thus allow the user to order all the different parts of the iuniform. I can create this for 1 Uniform Linking the Purchasing Category for the Uniform 1 to the relevant items but where an item exists in Multiple uniform BOM's