1. A computer-implemented method for building virtual node groupings within a grid environment, comprising: detecting a grid job at a particular grid manager from among a plurality of grid managers within a grid environment, wherein said grid job requires a particular degree of parallelism for execution, wherein a plurality of resource nodes within said grid environment are identified in physically disparate groups each managed by one from among said plurality of grid managers, wherein said particular grid manager locally manages a first selection of resource nodes from among said plurality of resource nodes within said grid environment within a particular physical location; accessing, from said plurality of grid managers, a current availability and workload of said plurality of resource nodes within said grid environment; selecting a second selection of resource nodes from among said plurality of resource nodes to build into a virtual node grouping for executing said grid job; and building said virtual node grouping by enabling said particular grid manager to acquire temporary management control over said second selection of resource nodes for a duration of execution of said grid job within said virtual node grouping, such that said grid job is executed within said virtual node grouping automatically built and managed by said particular grid manager within said grid environment.