Multiple email addresses in one field

[Los Feliz Slim]

In a database of contacts when someone uses multiple email addresses I enter them all in one field separated by commas. On the desktop when I run a script that sends an email to the contact it is sent to all the addresses (using an external email application). On FileMaker Go, however, instead of inserting each address separated by commas in the mail app, I get nothing - an empty "To:" field. I'd rather not have to add fields for those with multiple email addresses and feel like there's got to be an easier solution.

Thanks for any help!