N.J. Stat. Ann. § 2A:84A-21.7

Where proceedings are instituted hereunder by one of several co-defendants in a criminal trial, notice shall be provided to all of the co-defendants. Any co-defendant shall have the right to intervene if the co-defendant can demonstrate, pursuant to section 3, that the materials sought by the issuance of the subpena bear upon his guilt or innocence. Where such intervention is sought by a co-defendant, that co-defendant shall be required, prior to being permitted to participate in any in camera proceeding, to make that showing required of a defendant in section 3.