I have been added as a party to a lawsuit already in existence for 2 years. Entitled to all prior discovery, who pays cost of prior discovery?

There are probably 30,000 pages of documents in "prior discovery" and I would need those to adequately defend myself. Who pays for the cost to provide a newly added party with all pre-existing discovery? (The filing to add me was a shotgun pleading) I believe that the lawsuit is frivolous but the law firm in question here engage in sport litigation and have been cited by several other NJ judges in court cases for their non-RPC character and behavior (Lying to Tribunal, etc.)