Variable Conversion Factor for UOM?


I know it’s not there but does anyone know of a way to implement a variable conversion factor for an item, as opposed to a single fixed value in the Item master?

To explain…

One item we buy is an enzyme. Enzymes are purchased in a measurement of U/mg, for Units of activity per milligram (mg). This number of U/mg varies for every batch purchased, so I cannot set a single conversion factor like most other items.

Does anyone know of a way to assign a conversion factor per batch?