Hide Text/URL from Unauthorized

[dynamite]

I am looking for something that will allow me to hide certain parts of a post or automatically hide a URL from users who do not have sufficient priveldges. The only way I am able to currently do this is to put in an attachment and only allow those with proper authorization to download the attachment.
I wish it could be something like the license system used here where it just hides that particular part of the post and say you must be a X member level to be able to view this.
If there is already something like this, please point me in the right direction because I have tried every search combination I can think of, but am not finding what I want. Thanks!