How to map this scenario..?

Hi,

I have one requirement to map in SAP,

Scenario:

1)PO will be raised for a material A.

2)Material A contains 5 different component materials( ie by assembling 5 components we will get Material A)

3)When I do GR for Material A against that PO, stock has to be updated only for 5 components not for material A.

Can you pls tel me how to map this in SAP.

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Regds