Spitfire Traffic?

Is there a tool that I can use to merge 2 traffic .bgl's? I just bought the RealAir Spitfire which comes with an updated RAF West Malling Air Base and a traffic .bgl that adds AI spitfires flying around the vacinity of the airport, but FSX won't load that .bgl. Normal traffic displays, but it won't. It is in the Scenery, World, Scenery folder. Tips?