Ohio Rev. Code § 5705.48
Whenever a taxing district is located in two or more counties, the budget commission of the counties in which such district is located shall meet in joint session at the call of the chairman of the commission of the county in which the greatest value of taxable property of such taxing district is located, and adjust the rates of taxation for the purpose of such district so as to enforce the limitations on the tax rate prescribed by law and to produce uniform rates throughout the district. The levies for such taxing district purposes shall not be reduced by such joint budget commission below what would be required to enforce such limitation in the part of such district in which the least reduction of such levies is necessary to enforce such limitation, and such levies so fixed shall be applied uniformly throughout such district.
R.C. §5705.48