Using Open GL across multiple graphics cards

We are building an application that uses Open GL and (2) NVIDIA Quadro 2000 / K2000 family cards in a single windows workstation four monitor configuration. When we run the application we notice that the second graphics card’s resources are unused (using GPU-Z to monitor) and all the resources are piling up on the first graphics card. We’re trying to figure out how to make our application balance the load across the two units. Any advice/pointers appreciated.