In the conduct of institutes and group conferences as provided in this chapter, it is made the duty of the state-supported institutions of higher learning offering teacher-training courses to cooperate as far as practicable with the Department of Education in furthering training-in-service activities. The Department of Education in cooperation with the state-supported institutions of higher learning offering teacher-training courses shall arrange as far as may be practicable for extension courses as a part of or in lieu of group conferences hereinbefore provided. County superintendents of education and city superintendents of schools shall from time to time make known their training-in-service needs to the Department of Education, and the department through cooperation with teacher-training institutions shall endeavor to assist county and city superintendents in setting up and carrying into effect a training-in-service program.