static class StringExt {
public static IEnumerable<String> SplitInParts(this String s, Int32 partLength) {
for (var i = 0; i < s.Length; i += partLength)
yield return s.Substring(i, Math.Min(partLength, s.Length - i));
}
}
var parts = System.Guid.NewGuid().ToString().Replace("-","").SplitInParts(4);
But remember for retaining the uniqueness you need to have the 16 digits. You can also use guid.ToString("N") for getting number without '-', please try and use the whole GUID it is made for a purpose. :)
Please try this and post back your comments if this works out.
Thanks.