Limit Outlook 2003 SMTP connections to server

Sending large e-mail distribution lists (200+ recipients) causes remote mail server (pop3/smtp) to drop TCP connections. Note this is not spam mailers 🙂 I have a suspicion that Outlook tries to open as many SMTP sessions to the server as possible, causing above.

Any way I can limit the amount of smtp connections Outlook 2003 opens to the server? Or send a mail one by one to each recipient in the distro group?(e.g registry setting, 3d party software with Outlook etc etc)

Splitting distribution groups into smaller lists are not the answer I’m looking for.

Much appreciated.

Stefan