using System;
using System.Text.RegularExpressions;

public class Example
{
   public static void Main()
   {
        string document = "***\r\nContent2\r\n***\r\nContent3\r\nContent3\r\n***\r\n\r\nContent4\r\n***\r\nContent5\r\n\r\n***\r\n***\r\nContent6\r\n***\r\n***\r\n***\r\nContent7";
        var records = Regex.Split(document, @"(?:\r?\n)?^[*]{3}\r?$\n?", RegexOptions.Multiline);
        foreach (string match in records)
        {
            Console.WriteLine("'{0}'", match);
        }
   }
}