Returning multiple view from spring controller

I want to return multiple views(jsp) from one controller. i.e. one view below another

@RequestMapping(method = RequestMethod.GET, value = "register")
public String addUser(Model model) {
    // on some condition
    if(){
     //add "user/login" above or below "user/edit"
    }
    model.addAttribute(new User());
    return "user/edit";
}