Hi Sarvan,
This is not possible in the standard SAP.
You can manage this requirement if you have APO throught a bottom up rescheduling (adding a custom logic).
If you don´t have APO, you will need to make a custom program to do this. It is quite complex but can be done. Now, there are lot of questions that you will need to know before trying to make a program like this: for example, if you have a remaning stock of SFG2, etc..
Kind Regards,
Mariano