How to control duplicate comments?

Hello:
Is there an option to disable duplicate comments?
For example let us say I want to use wpdiscuz comments to take a user survey “what is your favorite color?” and in the comment field they will give their answer… So if the comment “red” has already been submitted it will detect existing value and just give the user the option to vote up the already existing “red” comment.

As user types the comment, an auto-suggest will give a dropdown list of any existing comments…etc.

Make any sense?
Thanks!