(1) If the board of county commissioners determines by resolution that the pooling of bonds of more than one special improvement district of the county is in the best interest of the county and the respective districts and will facilitate the sale of the bonds under more advantageous terms or with lower interest rates, the county may issue bonds of the districts combined in a single offering. Such bonds must be secured by the rural special improvement district revolving fund of the county.
(2) The title of the bonds issued pursuant to this section shall denote that bonds of different special improvement districts have been pooled and shall refer to the numbers of the districts. The bonds must be drawn against a sinking fund that has separate accounts for each special improvement district combined for financing purposes, into which must be payable the assessments levied in each of the districts.