An intermediate school district and a constituent school district or districts wholly or partially within the intermediate school district’s boundaries may incorporate an authority for the purpose of acquiring, furnishing, equipping, owning, improving, enlarging, operating, and maintaining a building or buildings as a facility for disabled, developmentally disabled, or mentally disturbed children, and the necessary site or sites therefor, for the use of the intermediate school district and a constituent school district or districts pursuant to a contract between the intermediate school district and constituent school district or districts.