Whenever, after hearing, upon complaint or upon its own initiative, the Commission is of opinion that the divisions of joint rates, fares or charges, applicable to the transportation of passengers or property by common or restricted common carriers by aircraft or by such carriers in conjunction with common carriers by railroad, motor vehicle, express and/or water are or will be unjust, unreasonable, inequitable, or unduly preferential or prejudicial as between the carriers parties thereto (whether agreed upon by such carriers, or any of them, or otherwise established), the Commission shall by order prescribe the just, reasonable, and equitable divisions thereof to be received by the several carriers. In cases where the joint rate, fare, or charge was established pursuant to a finding or order of the Commission and the divisions thereof are found by it to have been unjust, unreasonable, or inequitable, or unduly preferential or prejudicial, the Commission may also by order determine what would have been the just, reasonable, and equitable divisions thereof to be received by the several carriers, and require adjustment to be made in accordance therewith. The order of the Commission may require the adjustment of divisions between the carriers, in accordance with the order, from the date of filing the complaint or entry of order of investigation or such other date subsequent as the Commission finds justified and, in the case of joint rates prescribed by the Commission, the order as to divisions may be made effective as a part of the original order.