Vista - How to force Outlook 2007 to allow a large number of "To's"

I belong to a large group that I send out emails to occasionally. Outlook 2007 on my Vista computer will not let me send to the whole group in one email. I have to split it into about 6 different emails to get it to go. When I was using Outlook 2000 on XP I did not have to do this. What setting can I use to force Outlook 2007 to accept all the addresses I want to enter so I just have to send my newsletter one time?

In a related question...Outlook 2007 will also hang up and not send the email to my group IF there is one email some where in the group that it does not like.
TWO QUESTIONS:
1) is there a way to force the email to go even if there is one bad address in the group and just bounce back an error message on the problem email?

2) Is there a way to make it tell me which email it has a problem with so I can manually remove it? Outlook Express will at least kick back a helpful error message and tell me what email address is causing a problem so I can just remove that name to make the email go to the rest of the people.

Thank you,
Cindy