Using a public custom form..

This is what I am trying to do:

I am an avid player of Epic Pet Wars. It’s like those iMob games. To increase your own power, you add people to your “posse” by adding their friend code. There are forum posts around the internet with people posting their friend code, but it seems messy. I also have it so people can comment on a blog post on my site, but it also gets messy and people like to re-add theirs by commenting again.

Since I can’t sit there and weed out duplicates in the comments section, and I can’t figure out a way to use cformsII to do this, is there another way to make it so people can input their 6 character friend code, submit, and have it publically shown on a table, and have it so that no duplicates are shown?