So you just want a script that will send to the approriate email address based on what they select. Our open source mail script may be able to help.
Link:
http://www.arecaweb.com/php/mmex/mmex.html
Then in the html form all you have to do is use this code below:
<select name="recipient">
<option selected>Choose a recipient</option>
<option value="email_1@domain.com">email_1@domain.com</option>
<option value="email_2@domain.com">email_2@domain.com</option>
</select>
(Goto site for more details and email us if you have any questions)