Do your visitors get to pick which address gets teh email or its it just a form that goes to everyone on a list?
What you need is server side processing, via PHP, Perl, etc. Lucky for you I wrote a "process pretty much any form all the config is really done in the form" processing script forever ago, still works well. And, I put it Out There under the GPL - so you can use and enjoy and share.
php-form2mail gruv.org