General extra material's requirement when MRP

Hi All,

I meet a problem in our company. We usually create PIR for our prodcut A, then run mrp general the PR, PR-->PO, PO GR come to stock, finially SO(product A) PGI to consume the stock and deduct the PIR. But now we want to general B material requirement at the same time when MRP for product A, we need to buy A and B at the same time. At last we will 311 transfer B to the special location and consume B by our special program. My question is : how to general B requirement at the same time when run MRP for A ?

I have 2 methods: 1) create another phantom material C = B+A ===> This is a little complex, and how to set and deduct PIR ? We don't want to add more new materials; 2) use enhancement/BAdi to create B on the PO when create/change A PO ===> When first we only have PIR on A, we don't know B requirement at that time.

Do you have more better solution? Thanks!

BR,

Microfish