Send more than 2 emails

Hello,
i’ve been looking for a while now and can’t seem to find anything that helps, or anyone that had the same need before.

How can i send more than 2 emails from the form action?
Let’s say i want to send an email to the webmaster, an email to the user and an email to a third person who is supposed to make an estimation.. how can I set this up?

Thanks
L.