The provisions of the trust indenture entered into by the Governor on July 1, 1996, with the West Virginia trust fund, inc., acting as the trustee, are superseded by the following provisions:
(a) The board shall continue to hold each of the participant plans specified by this article in a separate irrevocable trust as trustee pursuant to the terms and provisions set forth in this section and with the earnings and losses accounted for and charged individually to each participant plan and trust: Provided: That the board shall be authorized to invest the assets held in each participant plan in any investment fund even though the board may also invest non-401(a) moneys in the investment fund. Participant plans, each declared by this section to be held in a separate irrevocable trust, include, but are not limited to, the following and any other plans that may be added to this section or otherwise designated by the Legislature from time to time:
(1) The public employees' retirement system;