You have to think about the purpose of a jockey pump. If the water supply has a lot of fluctuations in pressure, it could trigger the alarms of a wet sprinkler system. To prevent these false alarms,a jockey pump maintain a higher pressure than the municipal water pressure above the sprinkler valve clapper. So why would you want the domestic water service presumably supplying the sprinkler system act as a jockey pump?--unless I am misunderstanding your question or not all the details about your situation are not provided.