Drupal Webform Validation

I have a Drupal Webform that has to work this way: - There are some category (6 or 7) - There are several names in each category (8/25) - Authorized users can vote (select) EXACTLY 5 names - Authorized users can give 1 to 5 stars rating to each name they choose, but this value must be UNIQUE. So if the user gives 2 stars to one of the names he can't give 2 stars again to another. He has to give a different rating to each name. The firs part (5 selections) would be easy with webform-validation module, but I don't know how to achieve the UNIQUE value for the given stars (or points, I don't care if they are stars, numbers or whatever) Find attached the printed version I used until now and the jpg image of a possible webform version of a single category (numers and fivestars are alternative). The example in the jpg has a single descripion field instead of the 3 you see in the paper version. This is allowed if it make it easier for you.