Hi Vadamalai,
Option 1 :
Instead of going to BSEG table . You can use Secondary index tables : like BSAK, BSIS, BSAD, BSID.
Option 2:
First Go to BKPF table. Get your required Accounting document nos. then take that all accounting document no and financial year in range table, and Pass the Accounting document no and Financial year to BSEG table . Then Delete records which you don't need using DELETE statement.
Thanks,
Naren.