(A) The owner may include improvements that are proposed to be funded by multiple districts, known as a "collective improvement". The owner and the governing body may agree to designate all or part of the improvement fee for the construction of the collective improvement. If this occurs and if the collective improvement has not been identified previously in an improvement plan for another district, then the improvement plan must include:
(1) a description of the collective improvement;
(2) the estimated cost of it;
(3) a deadline by which the collective improvement must be initiated; and
(4) provisions for alternative uses of the improvement fee to defray the cost of other improvements within the same service area if the collective improvement is not initiated within the approved timeline.
(B) The improvement fee or portion allocated to a specific collective improvement must be deposited into a trust account maintained by a bank serving as trustee in connection with bonds or other obligations secured by assessments. This trust account is to be maintained only for the purpose of funding a specific collective improvement. Funds from multiple districts, including districts that are created after the creation of the trust fund and the identification of the collective improvement, may be commingled in these trust accounts for the purpose of funding the collective improvement.