I have a commercial property that has a fence dividing a field from the manicured area. The field has wild grass and the manicured area has St. Augustine grass. There are two zones irrigating both ends of the property. I need to disconnect the area that irrigates the field without disconnecting the other area. I guess dividing the zones. I have only replaced sprinkler heads, I have no experience at irrigation work beyond that. How do I stop the system from irrigating the field without plugging the line to that area?