using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        var MerchantHost = "intellectmoney.ru";

        var arrDomains = new string[] { "intellectcard\\.com", "intellectmoney\\.ru", "localhost" };

        string domainsPattern = string.Join("|", arrDomains);

        var ownDomainRegex = $@"(\.|^)({domainsPattern})$";

        var test = Regex.IsMatch(MerchantHost, ownDomainRegex);

        Console.WriteLine(test);

    }

}