Hello Mohit,
You need a custom solution.
It can be done by using custom program to delete planned orders or Pur Req without source of supply. This program can be run immediately after SNP Heuristics and/or then again after Capacity Leveling.
You will require this BAPI : BAPI_MOSRVAPS_DELEMULTI
Hope this will help.
Thank you
Satish Waghmare