Substitute Item applicable for One Work Definitions but not applicable for another

Summary:

We have a requirement where Substitute Item is applicable for One Work Definitions but not applicable for another. For example. FG Item A has component C. Also, FG Item B has component C. Component C has a substitute which is Component D.

Now, when there is a demand for Item A, Substitute component D can be used (when C in not on hand)

But when the demand is for Item B, Substitute component D cannot be used (when C in not on hand.)

Client is using Process Manufacturing and does not have an Item structure.

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