How to Do in Nav 5.0 SP1 IN ?

Hi All,

We have a Client/Customer (Trading) in Nav 5.0 SP1 IN. Their main business is to sell different kinds of Bearings. And we all know that bearings can be assembled by two or more components, which can be items.

The Scenario

A is an Item, and Components of A are B & C.

If any Case in the Inventory shows that
A inventory = 1, B Inventory = 0, C Inventory = 0
At that time Client can Sale the Item B because it is a part of A.

But How can I do this ??

What is the setup/flow to do this??Please Explain.