(2) It shall be unlawful to receive or record such plat or replat or deed in any public office unless the same bears thereon the approval, by indorsement, of such commission or city engineer. However, the indorsement of the commission or city engineer of the city with boundaries nearest the land such document affects shall satisfy the requirements of this section in case the boundaries of more than one city are within six miles of the property so mapped or described. If the governing bodies of such cities mutually agree upon a boundary line establishing the limits of the jurisdiction of the cities other than the line equidistant between the cities and file the agreement with the recording officer of the county containing such boundary line, the boundary line mutually agreed upon shall become the limit of the jurisdiction of each city until superseded by a new agreement between the cities or until one of the cities files with such recording officer a written notification stating that the agreement shall no longer apply. [Amended by 1955 c.756 §27; 1983 c.570 §5; 1991 c.763 §25]