using System.Collections.Generic;
public static void Main()
var settings = new List<DocumentNotification>
new DocumentNotification{Email = "abc.com;def.com", Identifier =null},
new DocumentNotification{Email = "abc.com;def.com", Identifier = "1234567890"}
var receivers = new List<string>();
receivers.AddRange(settings.FirstOrDefault(x => x.Identifier == null)?.Email?.Split(";") ?? Enumerable.Empty<string>());
receivers.AddRange(settings.Where(x => x.Identifier == "1234567890" && !string.IsNullOrEmpty(x.Email)).Select(x => x.Email.Split(";")).SelectMany(x => x));
Console.WriteLine(receivers.Count());
foreach (var r in receivers)
public class DocumentNotification
public DateTime CreatedDate
public DateTime UpdatedDate