Help with travel query

We provide a mobile service and we have bookings and service providers, we allocate service providers to bookings and we pay the mileage based on the journey distance, from the service providers home to the booking, this is fairly straight forward if they only work one booking in a day but when they work 2 bookings in a day, we would pay them mileage based on their journey from home to booking 1 to booking 2 to home. is there a simplish way to achieve this,