GpuMat submatrix out of GpuMat object?

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Since accessing pixels in GpuMat object is not possible, is it possible to create GpuMat sub matrix out of main GpuMat matrix with defined range or ROI and how? Transferring GpuMat to Mat and then again to GpuMat is not an option, since memory transfers will actually slow down my program. Thanks in advance.