using System;

using System.Collections.Generic;

using System.Globalization;

using System.Linq;

​

public class Program

{

    public class SwiftCodeInfo

    {

      public string Country {get; set;}

      public string SwiftCode {get; set;}

      public string BranchCode {get; set;}

    }

    public class BranchCode

        {

          public string Country {get; set;}

          public string SwiftCode {get; set;}

          public List<string> BranchCodes {get; set;}

        }

    public static void Main()

    {

        var swiftCodeInfo = new List<SwiftCodeInfo>();

​

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="USA", SwiftCode ="ABCDEFGH", BranchCode="101"});

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="USA", SwiftCode ="ABCDEFGH", BranchCode="102"});

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="USA", SwiftCode ="ABCDEFGH", BranchCode="103"});

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="USA", SwiftCode ="XYZABCDEF", BranchCode="104"});

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="USA", SwiftCode ="XYZABCDEF", BranchCode="105"});

swiftCodeInfo.Add(new SwiftCodeInfo{Country ="IND", SwiftCode ="ABCDEFGH", BranchCode="106"});

        var result = swiftCodeInfo.GroupBy(l => new { l.Country, l.SwiftCode })

             .Select(g => new BranchCode {

                    Country = g.Key.Country, 

                    SwiftCode = g.Key.SwiftCode, 

                    BranchCodes = g.Select(i => i.BranchCode).ToList() 

                });

        foreach(var item in result)

            Console.WriteLine(item.Country+" "+item.SwiftCode+" "+ string.Join(",",item.BranchCodes));

    }

}