I am needing to send out some mass emails to people who are in my contacts list.  However, I keep getting blocked out because Hotmail is automatically assuming that I'm a spammer. 

These are emails to people who have voluntarily signed up for updates.  I've already divided the emails into groups of less than 50, but no sooner do I get one email sent out than I get blocked out of the account.

How do I manage this?