Groups of cells in unstructured grid

If I have this unstructured grid like this:

vtkNew ugrid;
ugrid->InsertNextCell(VTK_HEXAHEDRON, 8, pts[0]);
ugrid->InsertNextCell(VTK_HEXAHEDRON, 8, pts[1]);
ugrid->InsertNextCell(VTK_TETRA, 4, pts[2]);
ugrid->InsertNextCell(VTK_TETRA, 4, pts[3]);
ugrid->InsertNextCell(VTK_POLYGON, 6, pts[4]);
ugrid->InsertNextCell(VTK_TRIANGLE_STRIP, 6, pts[5]);
ugrid->InsertNextCell(VTK_QUAD, 4, pts[6]);
ugrid->InsertNextCell(VTK_TRIANGLE, 3, pts[7]);
ugrid->InsertNextCell(VTK_TRIANGLE, 3, pts[8]);
ugrid->InsertNextCell(VTK_LINE, 2, pts[9]);
ugrid->InsertNextCell(VTK_LINE, 2, pts[10]);
ugrid->InsertNextCell(VTK_VERTEX, 1, pts[11]);

How can I create groups (f.e. Triangles, Lines, Quadrilaterals) and then identify these groups in paraview.


See my answer here: Unstructured grid with different type of elements (triangle and lines) - #5 by Sagues