Two (2) or more counties that have qualified for participation in the state's multi-county regional library program and that have been recognized as a region by the secretary of state and have made the minimum local appropriation of funds that may now or hereafter be required by the secretary of state, are empowered and authorized to execute contracts with each other to create a regional library board to assist the secretary of state, acting through the division of public libraries and archives, in administering and controlling the regional library services within the region. Each county shall be represented by two (2) members of the regional library board. The contract shall be authorized by a resolution of the legislative body of the county desiring to participate and the county mayor shall execute the contract as authorized in the resolution, and the contract shall be attested by the county clerk. After the governing body of a county authorizes participation, municipalities within the county may participate in the regional library service so long as the county participates. A city in a county not participating in a region can, with approval by the secretary of state, join the state regional system as related to state purchasing contracts. The secretary of state shall assess fees, from participating cities, for any additional cost of services under the state contracts. Counties and municipalities may appropriate funds for this purpose. A single county that is large enough to constitute a region and has been so recognized by the secretary of state may also create a regional library board by executing a contract between the county and one (1) or more cities within the county. There shall be at least seven (7) board members apportioned among county and municipalities according to the ratio of population in each participating municipality and in the county outside the municipalities, based on the most recent federal census.