Change 'Zip' in Groups add form...

I'd like to modify the 'Zip' field in the Groups add form to be a 'Website' field. The name change is easy with a language key change. However, when testing this the output box on the created event page (now called 'Website') cuts the input text to 16 characters and obviously does not enable the input to be clickable as a link. Ideally I'd like "http://" to be automatically embedded for the user to enter their site/link after and also allow it to be parsed as a clickable link. Any ideas?

Any thoughts on this one?