using System;
using System.Linq;
using System.Collections.Generic;
 
public class Test
{
	public static void Main()
	{
		var txt = @"John Doe    000115   
Wilson Chan 000386
Tye Owens   000589
James Peter 000211
Carl Spade  000445
Sally Doe   000213";
		var splits = txt.Split('\n')
			.Select(m => new KeyValuePair<string,string>(m.Substring(15,2), m))
			.GroupBy(z => z.Key)
			.Where(y => y.Count() > 1);
		foreach (var x in splits)
		{
			Console.WriteLine("--- {0} ---", x.Key);
			foreach (var y in x)
				Console.WriteLine(y.Value);
		}
	}
}

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