Radio Button for Approval flow

I am creating a form in Acrobat, when the user filled this form he has to choose all the departments thats needs to approve the document, only receiving an email. For example, he choose 3 departments:

1rs Logistic; 2nd Productio, 3rd Quality

I need a rule that check if radio button (or another kind of button) is filled, if yes when i push the "send" button the email will be created for this second department...I don´t know if I make myself clear...

Someone? Help!