To be exact, Outlook 2000 limits the number of recipients... I don't know the number, but for Outlook 2003 it's 64,000.
However, the problem isn't actually there. The SMTP RFC states that an email address can have a maximum of 64 characters before the @ and 64 after... Therefore, all SMTP servers would need to accept a string of: 82,560,000 characters...
So the limitation in general is not a number of recipients but a string size... Sometimes 30 recipients may be enough to block if their addresses are very long...
So there are 2 possibilities... use an emailing principle... with as many emails as there are recipients... otherwise, break it down into small distribution lists...
Good luck for the rest.
Sil