(1) A hospital service corporation and a professional service corporation may operate under joint management for the purpose of reducing operating costs.
(2) Separate records and accounts shall be kept for each such corporation, and the funds and assets of one shall not be commingled with those of the other; except that funds received from a joint billing to subscribers may be deposited in a common bank account for purposes of collection, if the records of each corporation at all times show the amount of such funds belonging to each and if final distribution of the funds is made to each corporation within thirty (30) days from receipt of payment of such joint billing.