Section 4. The school committee of any city, town or school district may, to meet its obligations under section three, with the approval of the department enter into an agreement with any other school committee to jointly provide special education or, subject to the consent of the parent or guardian affected thereby and subject to constitutional limitations, may enter into an agreement with any public or private school, agency, or institution to provide the necessary special education within the city, town or school district; provided, however, that every school committee, where feasible, shall be associated with an educational collaborative providing services to children with a disability which disability occurs in a low incidence in the population of children requiring special education.

In the case of an agreement between school committees to jointly provide special education, said agreement shall designate one city, town or school district as the operating agent. Funds received by such operating agent from other cities, towns or school districts or appropriated by such operating agent for the purposes of such agreement, in addition to gifts and grants shall be deposited with and held as a separate account by its treasurer. The school committee may apply said funds to the costs of programs operated pursuant to the agreement without further appropriation.