Customize search by category/everything else

I’ve seen a few others asking this question, but I’m not sure it’s been resolved. I hope someone can help. I’m creating a site that has creator-generated “official” content and a public-oriented section with user-generated content (sort of a chatroom made up of a blog entry and replies).

I can easily describe user-generated content as a single category, but I’d like to give visitors the option of searching either the single category of user-generated content (let’s call that category “user”) or everything else.

If that can’t be done, I’d at least like the results to be separated by website (minus “user”) and “user”. I’ve seen plug-ins that will remove categories from the search, but I’d like to still let visors search the category — I just want is separate from the official content.

Any advice? I am not a programmer/coder, so please feel free to talk down to me!

thank you,