The host file basically does the same thing as DNS but the list is generally much shorter because you populate the file. Thats why I was suggesting "OPEN DNS" because it's a server where a lot of the configuration was pretty much done for you.
If you have Advance Proxy with UrlFilter Installed you can do that from the Web-Interface. in URLFilter you can create a Blacklist and apply it on specific IP addresses or MAC's.
give it a try it is not hard to install nor to configure.
