Copy Shared Folder to GAL

I have a client who would like to copy the 1300 contacts they have in a shared Exchange Folder to the Global Address List to make them readily available from within Outlook when addressing E-mail.

I have not found a way to make this occur as the GAL is normally populated from Active Directory and their client/vendor list is obviously not part of AD.

Server is Windows 2003 Small Business Server.

Thanks,

jdg