Notwithstanding § 836.004 and to the extent required as a condition of plan qualification under Section 401(a) of the Internal Revenue Code of 1986 (26 U.S.C. § 401), the retirement system shall, in accordance with Section 401(a)(31) of the Internal Revenue Code of 1986 (26 U.S.C. § 401(a)(31)) and related regulations, permit the distributee of an eligible rollover distribution to elect to have the distribution paid directly to an eligible retirement plan specified by the distributee in the form of a direct trustee-to-trustee transfer. The board of trustees may adopt rules to carry out this section. Terms used in this section have the meanings assigned by the Internal Revenue Code of 1986 (Title 26, United States Code).