Not as a formal part of the dispatch system. Typically municipal ambulances are dispatched from ambulance/fire halls, or pre-positioned spots. Or at least they were when I moonlighted with EMS in Edmonton.
Doesn't matter where you are. There is just one question, "Is your stretcher clear?" It's a yes or no question. You can't lie, because the nurses are standing there watching and listening to your answer. So, you better tell the truth.
Alberta has a different regulatory system than Ontario. Both provinces have different regulatory systems than British Columbia, where the call occurred.
If you know an EMS service, that's what you know - one EMS service. That's all I know, other than what I have read about others since I retired.
We didn't have moonlighters or part-time police officers, firefighters or paramedics in Toronto. "It's a career, not a hobby!"