Fetching Alternate item Data from Order Confirmation SAP

Dear ABAP Experts,

Need your help to map the below requirement.

There is BOM of FG. It has 3 components, 1 semifinished and 2 packaging Drums.

The FG material at the time of confirmation(COR6N), may consume anyone of Packaging material depending upon the Packaging drum availability in stock.

To may this scenario, i have used the concept of Alternate Item group for both the Packaging Drum items.

I have assigned the same A1 with below screen shots in BOM of FG.

Based on my FG Material and their Batch in delivery(VL01N), I want to know the exact which drum is consumed against that Process Order.

So I want to know the Table and Fields to fetch the Particular drum being consumed in that process order.

Best regards

Shailesh