Creates a group for a tkp::canvas window. This code requires some extra work in order to deal with tkp::surface, too. A surface does not support any groups. Does not look feasible at all...
Example 3.65. ::vgcode::dump-configure-PathCanvas using pathgroup
... debug stdout "pathcanvas passed" } elseif { {group} == $type } { append _graphics \ [dumper::pathgroup $ta_name $id \ [dumper::itemproperties $optsl $id {} $target]]