using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            List<IntelHexModel> arr = new List<IntelHexModel>();

            arr.Add(new IntelHexModel() { RealAddress = 5 });
            arr.Add(new IntelHexModel() { RealAddress = 4 });
            arr.Add(new IntelHexModel() { RealAddress = 3 });

            List<IntelHexModel> arr2 = new List<IntelHexModel>();

            arr2.Add(new IntelHexModel() { RealAddress = 7 });
            arr2.Add(new IntelHexModel() { RealAddress = 15 });
            arr2.Add(new IntelHexModel() { RealAddress = 1 });

            List<IntelHexModel> arr3 = new List<IntelHexModel>();

            arr3.Add(new IntelHexModel() { RealAddress = 123 });
            arr3.Add(new IntelHexModel() { RealAddress = 2 });
            arr3.Add(new IntelHexModel() { RealAddress = 6 });
            arr3.Add(new IntelHexModel() { RealAddress = 66 });

            List<List<IntelHexModel>> test = new List<List<IntelHexModel>>();

            test.Add(arr);
            test.Add(arr2);
            test.Add(arr3);

            var orderd = (from subList in test
                          from subsubArr in subList
                          orderby subsubArr.RealAddress
                          group subsubArr by subList into ret
                          select ret.ToList()).ToList();
        }
    }

    class IntelHexModel
    {
        public int RealAddress { get; set; }
    }
}