ind_find_top_level_group.jsx

//@target "indesign"

var sel = app.selection[0];
var ret = find_parent(sel, 'Group');
function find_parent (obj, constructor) {
  if (obj.parent.parent.constructor.name !== constructor) {
    return obj.parent
  }
  else {
    return arguments.callee(obj.parent, constructor);
  }
  return null
}
if (ret) {
  ret.select();
}

// page/spread/story
//   top-level-group ---> select this group
//     parent-parent-group
//       parent-group
//         target