A.R.S. § 15-134

During the exchange teaching provided for in this article, the salaries of the exchange teachers or professors may be paid by either the school districts or universities or colleges by which they are regularly employed, or by the school districts or universities or colleges in which the exchange teaching service is rendered. The school district or university or college shall pay the salary of only one of the two exchange teachers and in an amount not to exceed the annual salary of its regularly employed teachers or professors.