When requested in writing by local school boards or boards of education, the board of each educational service unit may, at its discretion and within the limitations imposed by sections 79-1224 and 79-1225, (1) provide supplementary services to (a) the requesting school systems within its geographical area, (b) requesting school systems not within its geographical area to the extent allowed under the Educational Service Units Act, and (c) any other educational service unit, (2) plan and coordinate educational services within its geographical area whenever such services are offered on a cooperating basis between local school districts, and (3) contract for educational services with the board of any other educational service unit, any school district, any other educational agency, or any appropriate state or federal officer or agency, except that within that area of the service unit in which there exists an organized, full-time, approved city-county, multicounty, or regional health department with health services available, the educational service unit, if health services are provided, shall first seek to contract for school health services with such department for an amount of compensation agreeable to both such unit and board. The board of each educational service unit may charge for a portion or all of the costs of the additional services authorized by this section. If an educational service unit on December 25, 1969, has a health service facility, this section does not prevent the continued use by the unit of such facility. The educational service unit may contract with such health department to provide school health services for that area of the educational service unit not served by such city-county, multicounty, or regional health department.