It's not syphoning, just pumping at a pressure that while mid range doesn't make the cut off point of the pressure switch. Easy to do with yard hydrants... that I can get the plus side of 10 GPM out of, but if using standard hose outlets you need two of them running to stop the pressure from rising enough to kick off the pump.
Just lucky to be on a good water supply here, on a 185 foot deep drilled well, that I can suck that amount of water per day out of the earth!