BRUSSELS — Last week's settlement to limit the arrangements by which two big brewers have sewn up Mexico's beer market, the world's sixth largest, is unlikely to open the door to substantial competition there in the near future. After years of complaints from SABMiller, the world's second-largest brewer but barely a blip on the Mexican radar, global leader Anheuser-Busch InBev and third-ranking Heineken have agreed with regulators to curb exclusivity deals with Mexican retailers that have secured them a combined 99 percent of the market through their local units. Seen from the mature U.S. market, where SABMiller's joint venture with MolsonCoors is strong, Mexico offers much promise - it ranks fourth in the world for profit generated and is growing at a respectable 2 percent plus per year. The premium segment, an area of faster growth and fatter profits, is a mere 2 percent of the market now, compared with about 20 percent in the United States. And it is just over the border.