Pricing for doctors office

Hello, One of my clients works in a doctors office and asked if I would be interested in coming and giving 30 minute massages to 6 or 7 women who work in her office.  She has an electric table for me to use so no need to bring mine.  I have no idea how to price for the day since I have never done this before. These are complimentary to the employees by the doctor.  I live near Sacramento,Calif. if that helps for location  and pricing.  My fee for a session at my office is $65 for a 75 min session.  Can anyone give me some advice please?  Thank you.  Teri