Over the past few years much attention has been given to integrating multiple heterogeneous grids. Recently, an adaptor-based grid metascheduler has been proposed as a means to enable interoperation among different grids. However, one drawback of such approach is that when multiple metaschedulers participate in the grid all scheduling instances work in isolation, which in turn leads to poor load-balancing. In this paper, we propose a super-metascheduler approach which improves utilization and removes resource contention by centrally coordinating scheduling processes. Furthermore, it has the benefit of preventing other metaschedulers from disrupting local scheduling-policies because all cross-domain interactions are arbitrated at the super-metascheduler layer.