Defined Specification

We need to create one more spec for item (chemical using in pharma) that Buy from more than one Manufacturer (please note: Manufacturer, not Supplier) Another way to understand is, we do not buy raw material directly with the manufacturer but through an intermeditary distributor.

But for each manufacturer, we using another specification details (different list of test, or range of each test result)

We want to keep only one Item for using in Formula and Manufacturing, don't want create Item for each manufacturer (it can using with substitue). How to resolve this problem.