A method for controlling fluid flow. A valve system may be kept in an open state in response to a fluid being at a selected level of pressure at any of a plurality of ports in a valve. The valve system may be for the valve, and the valve may comprise a housing, the plurality of ports on the housing, and the valve system located inside the housing. The valve system may be configured to be in a closed state when an absence of the selected level of pressure is present at all of the plurality of ports and in the open state when the selected level of pressure is present at any of the plurality of ports. The valve system may be kept in the closed state in response to an absence of the fluid being at the selected level of pressure at all of the plurality of ports.