uPaged nurses are not employed by uPaged. They are employed by your hospital.
Every casual nurse who takes a shift at your hospital must sign a casual contract with that hospital at the first time of their first shift so that they can get paid via your payroll and covered by your insurances. Even when they are there to work for only one shift and may never work there again, it has to be signed. You won't need to do this for subsequent shifts worked at that hospital.
A nurse cannot be an employee of a hospital and then pick up shifts at that hospital with any nursing agency. Because uPaged nurses become an employee of the hospitals they work at, they cannot return to these hospitals as an agency nurse. However, as a casual employee of that hospital via uPaged, our aim is that uPaged nurses will be booked first and cancelled last by the hospital, and enjoy other benefits of being a casual employee of that hospital (ie: training and education, salary packaging, professional development etc).
Even though the hospital becomes the nurse's employer, the nurse choose the shifts with the rate of pay you want, and the nurse will always be a uPaged nurse as long as they continue to book shifts through the platform.