Sarvan,
You can have MRP propose two lots of SFG2 based upon lot sizing. For instance, if you always will want SFG2 to have orders of 50 each, then one way to achieve this would be to set the 'maximum lot size' to 50. MRP1 Tab of the material master.
There are other lotsizing methodologies that may be better suited to your business requirements as well.
Lot-Size Calculation - Consumption-Based Planning (MM-CBP) - SAP Library
Best Regards,
DB49