The officials of a political subdivision may plan the formation of a public corporation as a merged area to establish and operate an area hospital. In planning for an area hospital, a county board of supervisors may exclude from the merged area any township of the county which the board of supervisors determines would not sufficiently benefit by the merger and the portion of the county not so excluded shall constitute one public corporation for the purposes of this chapter. Plans for an area hospital shall include the maximum amount to be levied for debt service and operation and maintenance of the area hospital in the portion of the merged area within each political subdivision taking part in the merger. However, the maximum tax rates for the various political subdivisions may vary as the officials determine, based upon the need for hospital service of the residents of each political subdivision, the proximity of the residents to the proposed location of the hospital, the property values within the subdivision, and the expected service benefits to the residents of each subdivision by the proposed area hospital.