N.M. Stat. § 21-3-23
That in the event the board of regents of the New Mexico normal university [New Mexico highlands university] should find it advisable to issue bonds under this act [21-3-13, 21-3-14, 21-3-16 to 21-3-28 NMSA 1978] in more than one series, or at different times, for any or all of the purposes aforesaid, then each series of said bonds shall be designated by the letter "A," "B" or in some other designation, to the end that each series shall be kept separate, and all of the requirements of this act shall apply to and be faithfully followed, done and carried out as to each of said series; provided, however, that the board of regents of the New Mexico normal university [New Mexico highlands university] shall have no power to issue bonds hereunder, the aggregate interest and principal requirements for which, for any year, together with the aggregate principal and interest requirements for all outstanding bonds of such board for such year, shall exceed the amount of the income from the permanent funds and from the aforesaid income and current fund of said New Mexico normal university [New Mexico highlands university], received by the state treasurer for the fiscal year next preceding the fiscal year in which any bonds of such New Mexico normal university [New Mexico highlands university] are authorized to be issued by resolution of the board of regents.
NMS § 21-3-23