Any county and city located in such county are hereby authorized to create a joint county-city hospital authority, to jointly purchase, build, maintain and operate hospitals, hospital grounds, nurses homes, superintendent’s quarters and any other necessary buildings and equipment, on such terms and paying for the same in such proportions as such governing bodies of such county and city may determine, and may jointly operate any hospital or hospitals which are separately owned by the county or the city as a joint county-city hospital authority. A joint county-city hospital authority may be created under this chapter by joint agreement approved by resolution of the board of county commissioners of the county and the city council of the city. A joint county-city hospital authority created under this chapter shall be an independent legal entity with the powers set forth in this chapter.