Contact module to select multiple users

Is there a module to select multiple users as a registered user when using the contact. I created two categories (iste feedback for the siteadmin and contact all user), but I think there should be a possibility to select users as a registered user. I was thinking of a dropdown menu with the ctrl-option or a columnized overview of checkboxes next to users' names to check those you would like to send an e-mail to, e.g. you would like to contact directly.

Is there such an option in contact? Help would be very much appreciated!!! Thanks in advance!