Conditional e-mail recipients + select field: Email should not be revealed in html.

I want to send to different emails depending on a select box. BUT, I want to avoid revealing the email address in the page html.

Right now the visitor can use Firebug or "view page source" to have a look at all the email addresses in the select options. I would much prefer if the visitor would see some useless numbers instead.

Possible solution:
Instead of a key / label pair, the system could have a triple of key / label / hidden value, where only the key and label are sent in the html. The hidden value could then contain a bunch of email addresses.
I don't know how that can be easily defined via a textarea, but I think some solution can be found.