The school board or board of education of any school district may enter into contracts under such terms and conditions as the board deems appropriate, for periods not to exceed seven years, for the provision of utility services, refuse disposal, transportation services, maintenance services, financial services, insurance, security services, and instructional materials, supplies, and equipment and, for periods not to exceed four years, for collective-bargaining agreements with employee groups. This section does not permit multiyear contracts with individual school district employees.