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

public class Test
{
    class x
    {
        public int QuestionID;
    }
    class objx
    {
        public int RowNumber;
        public int DatabaseID;
        public int SetID;
    }

	public static void Main()
	{
	       var objY = new List<x>() { 
                new x{QuestionID=1}, new x{QuestionID=2}, new x{QuestionID=3},
                new x{QuestionID=4}, new x{QuestionID=5}, new x{QuestionID=6},
                new x{QuestionID=7}, new x{QuestionID=8}, new x{QuestionID=9},
                new x{QuestionID=1}, new x{QuestionID=2}, new x{QuestionID=3},
                new x{QuestionID=4}, new x{QuestionID=5}, new x{QuestionID=6},
                new x{QuestionID=7}, new x{QuestionID=8}, new x{QuestionID=9},
                new x{QuestionID=1}, new x{QuestionID=2}, new x{QuestionID=3},
                new x{QuestionID=4}, new x{QuestionID=5}, new x{QuestionID=6},
                new x{QuestionID=7}, new x{QuestionID=8}, new x{QuestionID=9}
           };
            var objX = objY.Select((x, i) => new { ObjX = x, Index = i })
                .GroupBy(x => x.Index / 5)
                .Select((g, i) =>
                    g.Select(x => new objx
                    {
                        RowNumber = x.Index + 1,
                        DatabaseID = x.ObjX.QuestionID,
                        SetID = i + 1
                    }).ToList())
                .ToList();
            
            foreach(var xList in objX)
                Console.WriteLine("Count: " + xList.Count);
	}
}