using System;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        var res = new[]{new

        {

        Group = 1, Status = 1

        }

​

        , new

        {

        Group = 1, Status = 2

        }

​

        , new

        {

        Group = 1, Status = 3

        }

​

        , new

        {

        Group = 2, Status = 1

        }

​

        , new

        {

        Group = 2, Status = 1

        }

​

        , new

        {

        Group = 3, Status = 1

        }

​

        , }.GroupBy(x => x.Group).Select(x => x.ToList()).Where(x => x.All(y => y.Status == 1)).SelectMany(x => x);

        foreach(var a in res)

        {

            Console.WriteLine(a.Group);

        }

    }

}