put two pressure switches on the tank and set at different pressures set (lest say the 1/2 gallon unit on the first switch, and if you use more water than the pumps out put, the second pump will kick on,
say the first one set at 40/60 and the second one 30/50 or similar first one will kick on at 40 pounds pressure and off at 60, the second will kick on at 30 and off at 50, so unless your pressure drops below the 40 pounds or the first well can't keep up and the pressure drops below 30 the second will kick on and give you additional water flow,
put a low water shut off on the well that may go dry,
http://www.deanbennett.com/bw-lh-systems.htm
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or even better use a large cistern or tank and fill it off of a float system, and then pump out of it with a jet pump for house pressure, (possibly with a low water shut off on the jet pump)