Essentially I do this every ride using an application named Ride With GPS. RWGPS has a Live Logging feature which allows another IPhone or Android device to see exactly where I am once I start a ride providing there is cell service. If cell service is lost while live logging, it will update once you gain service back. The transmitting phone in the bus would probably need a paid account but receiving phones only need the free account to see your location. You can limit receipt of your location by limiting it to Friends settings. Since I ride in a forest preserve and occasionally off trail, it allows a phone at home to see my location and route travelled in real time for safety reasons. RWGPS does allow you to submit a support ticket with specific questions on their app to see if it fits your needs.