(a) Notwithstanding any other section of this code to the contrary and subject to subsection (b) of this section, any qualifying municipality, as that term is defined in section two of this article, has the following authority:
(1) To close its existing pension and relief fund plan for policemen and firemen provided in article twenty-two of this chapter for policemen and firemen hired on and after a future date to be set by the governing body of the municipality;