An employer who elects to participate in the Post-Employment Benefits Trust Account shall be required to establish, fund, and apply distributions from the Post-Employment Benefits Trust Account, and administer a post-employment health, life, welfare, or other supplemental benefit plan or plans funded through the Post-Employment Benefits Trust Account, pursuant to applicable federal tax requirements or other legal provisions. An employer may expressly delegate its responsibilities under this section to the retirement system as described in subdivision (f) of Section 31694.1, to the extent allowed by federal tax laws.