Two middleware for only one Function in laravel

I can use only one middleware at a time..inside a constructor..I want to use if else condition inside constructor or two middleware.

I can use only only middleware inside constructor & if else condition also not working

I want only one function work or use according to middleware

Example are follows

If else

class HRJob extends Controller
   {   
       public function __construct()
       {
          if(Auth::guard('admin'))
         {
          $this->middleware('auth:admin');
         }
       else
       {
       $this->middleware('auth');
        }
    }
      public function userdetails()
      {
     dd(Auth::user());
      }
    }

Two middleware

class HRJob extends Controller
 {  
   public function __construct()
       {
     $this->middleware('auth:admin');
     $this->middleware('auth');
     }

  public function userdetails()
     {
     dd(Auth::user());
      }
 }

via Chebli Mohamed