Five brokerage giants team up on new East End listing platform Think fast, OREX — there’s a new contender in town. The five biggest brokerages in the South Fork — Saunders & Associates, the Corcoran Group, Douglas Elliman, Brown Harris Stevens and Sotheby’s International Realty — are teaming up on a new listing exchange they say will boast richer data at lower prices than the current local go-to, Open RealNet Exchange, or OREX.