I'm not sure how to do it in PHP (which appears to be what you're using), but in asp it's easy enough.
In the global.asa file put something like...
Dim nolink, ref
nolink = "http://www._.com/_/free-pedo-pictures-about-young-underage-12-years-olds-preteen-boys"
ref = Request.ServerVariables("HTTP_REFERER")
If nolink = ref then Response.Redirect("http://www.fbi.gov/")
It's not perfect because many users have selected to block referrer information (specially those kind of sick [email protected]
#$), but at least you will be able to do something about it.