Whenever underwriters, applying for certificates of authority hereunder, after the issue of such certificate, are joined by other underwriters, additional or substituted, such additional or substituted underwriters must comply with the provisions of this act, and shall be held to be bound by the documents on file with the Insurance Commissioner concerning such authorized underwriters, in the same manner and to the same extent as though they had been original applicants for the certificates of authority.
40 P.S. § 938