We are using Timesheet for managing task as well as OT for salary calculation

Hi sir ,
we are using Timesheet for managing task as well as OT for salary calculation.How can i manage these two separately.here we are using separate serial Number for Timesheet in OT (SSS-YYY-OT-)and Task(SSS-YYYY-TA-) .But while calaculating Salary system automatically taking both timesheet related to employee. Please help me to solve this issue.