I'm an agent, but also an HVAC designer (sorry to prove you wrong Mark about an agent not being an professional in this area, lol). What is confusing me is "pumps air" If your furnace is a forced air furnace that blows air through duct work you'd create multiple zones by adding control dampers to modulate air to different areas.
However, the discussion of pumps and switches makes me think that maybe this is a boiler system that is piping hot water for heating to radiators in the house. Maybe what you're referring to as switches are on/off valves. In that case, multiple pumps could make sense to better control hot water flow through the radiators.