I don't know how to eliminate posts from web-based newsgroup servers (like google.com).
HOWEVER...
if you use Outlook Express.... you can very easily eliminate that specific posts (and and all subsequent posts from the same sender) by doing the following:
Click on MESSAGE and then click on BLOCK SENDER. You will NOT get a confirmation == so be sure the message highlighted is the one you want to be rid of.
If you accidentally click and remove the wrong post (or eliminate an RCTQ friend!!) -- you can go to TOOL --> MESSAGE RULES --> BLOCKED SENDERS LIST ... and select the individual you didn't mean to block and remove them from the blocked senders list.
Any messages that come from the blocked senders email address will be blocked. However -- all too often these idiots often create new email addresses for each new "attack". So you may have to do it again and again.
But it does let you get rid of those horrid posts!
Kate in MI