如何使用c#和facebook API在facebook群组中发布状态

我可以发布到facebook墙，但我应该如何在一个组发布状态?

 public void Wall_Post_Publish() 
 { 
 FacebookClient app = new FacebookClient(); 
  dynamic parameters = new ExpandoObject(); 
    parameters.access_token =     ConfigurationManager.AppSettings["AccessToken"]; 
    parameters.message = "This is a test message that has been published by     the Facebook C# SDK on Codeplex. " + DateTime.UtcNow.Ticks.ToString(); 
    parameters.attribution = "Facebook C# SDK"; 
   dynamic result = app.Post("/me/feed", parameters); 
  Assert.NotEqual(null, result.id); 
 }

但是如何在组

dynamic result = app.Post("/group-id/feed", parameters);