Material determination in STO

Hi ,

Pls let me know how below described scenario can be achieved in STO in R/3 4.7 or ECC 6.0

PLANT1 needs material 'A' and it wil raise STO PO with supplying plant PLANT2.

But PLANT2 may no longer have inventory of material 'A' but may have inventory of replacement parts Material 'B' or 'C'.

PLANT2 may ship material 'B' or 'C' depending upon availability of stock. PLANT1 need to do the Goods Receipt against material 'A'.

Warm regards,

P.Saravanakumar.