Cooperation among rating organizations or among rating organizations and insurers in rate making or in other matters within the scope of this chapter is hereby authorized, provided the filings resulting from such cooperation are subject to all the provisions of this chapter which are applicable to filings generally. The commissioner may review such cooperative activities and practices and if, after a hearing, he finds that any such activity or practice is unfair or unreasonable or otherwise inconsistent with the provisions of this chapter, he may issue a written order specifying in what respect such activity or practice is unfair or unreasonable or otherwise inconsistent with the provisions of this chapter, and requiring the discontinuance of such activity or practice.