Add vendor drawing in item enry form

I want to be able to store vendor drawings for my inventory items...  I need to create a mapping between vendor item code, a field that contains that vendors drawing for that code, and add that field to the vendor list on the basic tab of the inventory item entry form... 

The issue I am encountering is that this cannot be an item field because I may have multiple vendors for a single item each with their own drawing...

any help would be appreciated...  would be willing to pay for some pro help if needed...


Thanks