Build me an EMT App

I need an app for a private ambulance service. This app will have to be for IOS & Android, and be able to be installed on individual devices not published on the stores. There will be three features on the app: despatching, being sent out and walkie talkie. Despatching: All members should have the ability to despatch, they should have to put in a road name, name & notes (incident). The road name field should be set to Basel, CH so that it comes up with suggestions as one types. When the despatcher hits the despatch button it will ask how many members to send out and then once clicked it will send out the chosen amount of closest members. The option should be 1-5 members or all. All emergencies should be saved in an area called "incident history". Receiving: As soon as a call comes in the members receiving the call should receive a push notification that will start ringing loudly until he open the app and its on his way. Once he presses that it will show him the road name, name and notes (incident). Walkie Talkie: At all times there should be a round icon in the bottom right corner so that all members can talk, if the app is closed and they start talking there should be a loud notification until he open the app or the notification. Anything that gets said over walkie talkie should be recorded and saved. All members whom have the app downloaded should be tracked at all times, even when app closed. My budget is low but its for charity, this organisation is totally non-profit.