CHURUBUSCO, Ind. (Nov. 17)—The Rubber Industry Buyers Alliance Inc. has gained two new members—Acushnet Rubber Co. Inc. and Trostel Specialty Elastomers Group—bringing its ranks to five companies. New Bedford, Maine-based Achushnet produces a wide variety of parts for the appliance, automotive and electrical industries. Trostel Specialty Elastomers Group is a member of the Albert Trostel Packings Ltd. family of businesses which make automotive and industrial seals. Charter RIBA members BRC Rubber Group Inc. and Alco Industries formed RIBA in May as a way of easing margin pressures brought on by customers´ demands for lower prices and higher supply costs. In June, American Rubber Products Corp. joined the buyers´ alliance.