Security: Hide direct referer

[Surfy]

I have many hidden (Usergroup specific) Boards..

My Errorlog is full from Peoples who try to get Access to such hidden topics.

I inverstigate, that Webmasters view and follow the Referers. (Some posts link to their Page)

How could i made a save referer for all links?


So that if i post a link, and someone click on it, nothing like this appears:

http://www.yabbse.org/community/index.php?board=141;action=post;title=Start%2Bnew%2Bthread

Better something like this:

http://www.yabbse.org/referer.php

I hope someone could help

Surfy