Add more than one pay rate for an employee

We have employees that get stipends that require them to manually enter them in as regular pay, FLSA, and regular overtime. Currently, there is only one pay rate available that we use as a base rate and have to enter each individual stipend pay in a new line into the system. We are asking to add in multiple pay rates under each employee so that it will automatically calculate all the stipends by only entering in one entry per day.