The chief elected public officials of various counties and/or cities of the economic development districts established under chapter 14 of this title, are empowered to create a human resource agency. It is the intent of this chapter that there may be four (4) metropolitan human resource agencies, Memphis-Shelby, Nashville-Davidson, Knoxville-Knox, Chattanooga-Hamilton, and no more than nine (9) rural human resource agencies, coterminous with the boundary lines of the development districts. It is the further intent of this chapter that the agencies so created may be the delivery system for human resources, and in no way an infringement on the planning functions of the development districts.