Inventory, per supplier, and a little extra

I am trying to faciliate my ordering form suppliers by being able to get a report of all items purchased by a supplier, including replacement items bought by other suppliers.


I order products a,b,c,d,e,f and g from supplier 1

I want would like to create a report listing the current inventory of all those items.

But, there are replacement products that are bought ffrom supplier 2:

products a1, b2 and c1(which are pretty much identical to products: a,s and c

I’d like to add those products to the report as well.

Ideas on how to create such a report?