How to establish parent and child relation for an Inventory item ?

Hi,

We have a scenario where we would like to have only one item (Main/Parent) under which we would like to have associated sub classification(Child/Subclass)

on PO we would be picking up Main item along with the child.

Business Case :  We are in the construction industry where lot of spares consumption (consumables)  would be there for the main item, to avoid huge inventory item creation maintenance in ERP, we are looking for parent and child relationship.

Appreciate if anyone can help me in mapping this requirement through seeded functionality

Thanks

Naveen