Hi Satish,
In my opinion you have to extract the Sale Orders and then the P.Req and/or Pl.Ord (with BAPI) to can achieve what you want. Then based on the BAPI's Input/output node you will be able to have the pegging from SO to pl.order.
To extract you can use: T.Code SE37
Read data from planning book - BAPI_PBSRVAPS_GETDETAIL, BAPI_PBSRVAPS_GETDETAIL2
Read Receipt and Requirement - BAPI_PPDSSRVAPS_GET_IO_NODES
Read Sales Orders - BAPI_SLSRVAPS_GETLIST2
Read Procurement Orders for Selection Criteria - With Characteristic-BAPI_POSRVAPS_GETLIST3
Read Manufacturing Orders for Selection Criteria - BAPI_MOSRVAPS_GETLIST2
Read Stocks for Selection Criteria - BAPI_STSRVAPS_GETLIST2
Gets the Linked Objects - BAPI_REL_GETRELATIONS
Hope that can help you.
Thanks.
Regards, Marius