Blocking queries to & responses from a given NS

[usenet at linuxnuts.net]

I'd like to figure out how to block queries from being sent to specific
NSs or NSs within certain domains.  I did this 4-5 years ago in the
peak of my spam fighting days but I can't recall how to do it now.
Back then I recall a couple spammers that always used the same NSs for
thousands of their spamming domains.  I "null routed them in DNS" (for
lack of the proper term) and prevented any queries from being sent to
them.

The reason I'm again interested in this is because of an article I just
read over news.com regarding typo domains and how a very large
percentage of those domains are handled by half a dozen companies.

http://news.com.com/Microsoft+tool+hunts+down+typo+squatters/2100-1029_3-6060935.html?tag=st.rc.targ_mb

If I could effectively block queries being sent to their NSs I could
lessen the impact their phishing/popup sites have on my userbase.  I
could simply do add a couple rules to the host-based firewalls on my
NSs or I could block it at the network level with an ACL.  I'm
wondering what the Bind method is.

Thanks
 J