Group of companies doctrine can bind non-signatories to arbitration when mutual intent is shown through corporate affiliation and conduct. The group of companies doctrine permits binding a non-signatory group member to an arbitration agreement where, despite separate legal personalities, corporate affiliation and party conduct demonstrate a mutual intention to arbitrate. Membership in a corporate group is a relevant but insufficient factor; tribunals must examine the words of the arbitration clause, commercial circumstances, and the non-signatory's role in conclusion, performance, or termination of the underlying contract. The claimant seeking joinder bears the burden of proving the cumulative indicia of consent.