(a) This chapter applies only to a local government that has all or most of its territory located in a county with a population of more than 1.3 million.
(b) Two or more local governments may act jointly under this chapter if:
(1) each local government is individually authorized to act under this chapter;
(2) all or most of the territory of each local government is located in the same county or in adjacent counties; and
(3) the local governments act jointly to perform each official act.
(c) Local governments acting jointly may perform any act that a single local government may perform under this chapter.