Need to be able to limit emails sent per hour

[Emil]

Hey! I'm going to re-launch an old forum so I would need to send out an email to all users once it's up. But the problem here is that my host won't allow me to send out more than 500 emails per hour and I have over 15,000 users on my forum. They suspend the account right away if there is too much email activity going on.

Is there any way to modify the code so that my vb doesn't send out more than 500 emails per hour when I email all users through the admin cp?

All help is highly appreciated!