function expandGroup(varArgs) {
      var args = Array.prototype.slice.call(arguments);
      var arg0 = args[0];
      if (args.length == 1 && arg0.indexOf(groupingDelimiter) != -1) {
        expandCollapseGroup(arg0.split(groupingDelimiter).length - 1, arg0, false);
      } else {
        expandCollapseGroup(args.length - 1, args.join(groupingDelimiter), false);
      }
    }
@param varArgs Either a Slick.Group's "groupingKey" property, or a
    variable argument list of grouping values denoting a unique path to the row.  For
    example, calling expandGroup('high', '10%') will expand the '10%' subgroup of
    the 'high' group.