Miss. Code Ann. § 41-27-19

Two or more counties may combine for the purpose of carrying out the provisions of this article in the respective counties, each county retaining all rights set forth in this article. The commissioners in the counties combined may enter into agreement to employ for purposes of economy, the same director and other personnel for the work of the commission in the counties so combined, all expenses, including salaries, labor, material, and the like being paid by the county in which the work is performed.