I don't know, but it sounds like you are asking for a change in
AwStats (a completely unrelated software), not the service provided here.. I'm surprised that Hostony is even offering to help with this, way to go Hostony!
But, a quick an dirty way to do this would be to make a script that directly removes those addresses from your log (or a copy of it) before AwStats processes the logs..? With the crontab.. or something.. when they're dumped into your home directory.
It seems to me the SkipHost option would cause these hosts to be ignored for all domains on that host, and if it's shared virtual hosts that's no good. It might be possible to do something with the Include directive and have a file in each user's home directory with the hosts they want to skip, but I don't know how flexible is AwStats for this.
I was looking at AwStats lately because it's a HUGE resource hog and many providers simply don't use it (thanks Hostony). It's a shame that there's no stand alone version for windows, otherwise people could just do their own graphs when they check their logs. (You need to install ActiveState's complete Perl distribution if you want to run AwStats on Windows).