For the purpose of facilitating the payment of the joint costs, expenses, salaries, wages, or other compensation, the agreement may also provide for the payment by each district of its proportionate share of the costs, expenses, salaries, wages, or other compensation, into the funds of any one of the districts which may be designated for the purpose, and the designated district shall thereafter pay all the costs, expenses, salaries, wages, or other compensation incurred by, or to be paid in connection with the maintenance of the joint organization.