Exchange 5.5 & smarthosts

If using a smarthost for SMTP delivery does Exchange 5.5 send an email multiple times if its addressed to mutliple recipients or does it send 1 copy and expect the smarthost to expand the email?

Or is there a way to make it only send one copy of the email? We are connected via a pay per minute satellite link and the less data we can send across the link the better!

TIA