A computer-implemented method for transmitting an email message from a sender addressed to both a first recipient and a second recipient, the first recipient capable of receiving email messages having a first email address compliant with American Standard Code for Information Interchange (ASCII) and the second recipient capable of receiving email messages having a second email address as a non-ASCII email address compliant with a non-ASCII email address format, the email message having a message body and a message header, the method comprising the steps of: identifying the second recipient by the second email address and sending the email message to the non-ASCII email address as a first transmitted email message, the first transmitted email message header including the second email address in a non-ASCII email address format and also including the first email address in an ASCII email address format; creating a corresponding first mapped ASCII email address for the second email address currently in a non-ASCII email address format by: generating a username as a mapping of the non-ASCII email address format using a predefined mapping algorithm; selecting a domain name from one or more predefined domain names, each of the domain names configured to resolve to a predefined gateway server; and concatenating the username and the selected domain name to create the first mapped ASCII email address for the second email address; replacing the second email address in a non-ASCII email addresses format with the corresponding first mapped ASCII email address; and transmitting the email message as a second transmitted email message to the first recipient using the first email address, the second transmitted email message header including the first email address and also including the corresponding first mapped ASCII email address representing the second email address. identifying the second recipient by the second email address and sending the email message to the non-ASCII email address as a first transmitted email message, the first transmitted email message header including the second email address in a non-ASCII email address format and also including the first email address in an ASCII email address format; creating a corresponding first mapped ASCII email address for the second email address currently in a non-ASCII email address format by: generating a username as a mapping of the non-ASCII email address format using a predefined mapping algorithm; selecting a domain name from one or more predefined domain names, each of the domain names configured to resolve to a predefined gateway server; and concatenating the username and the selected domain name to create the first mapped ASCII email address for the second email address; generating a username as a mapping of the non-ASCII email address format using a predefined mapping algorithm; selecting a domain name from one or more predefined domain names, each of the domain names configured to resolve to a predefined gateway server; and concatenating the username and the selected domain name to create the first mapped ASCII email address for the second email address; replacing the second email address in a non-ASCII email addresses format with the corresponding first mapped ASCII email address; and transmitting the email message as a second transmitted email message to the first recipient using the first email address, the second transmitted email message header including the first email address and also including the corresponding first mapped ASCII email address representing the second email address.