The City, through its duly authorized representatives, shall negotiate in good faith with a recognized employee organization which primarily represents firefighters on all matters relating to the wages, hours, and other terms and conditions of City employment, including the establishment of procedures for the resolution of grievances concerning the interpretation or application of any negotiated agreement. Unless and until agreement is reached through negotiations between the City and the recognized employee organization for the fire department bargaining unit which primarily represents firefighters, or a determination is made through the arbitration procedure hereinafter provided, no existing benefit or condition of employment for said fire department employees shall be eliminated or changed.