Using mod_rewrite I'd (ideally) prefer to capture a spacific ID from the URL inside a variable from the RewriteCond pattern match for (e.g.) /index.php?option=com_content&view=article&id=984&Itemid=131 for doing things later inside a RewriteRule.

I do not have trouble writing the pattern, but can't discover if this sounds like really possible, despite reading the docs. Has other people attempted this or know so that it is impossible?

The website is made on Joomla 1.6 (which adds IDs to Search engine optimization-friendly Web addresses), and I am attempting to steer clear of the overhead of something similar to HP Router simply to change a particular number of Web addresses.

The next should work. Use a % sign to gain access to the particular groups in the RewriteCond

RewriteCond %{QUERY_STRING} Itemid=([0-9]*)$
RewriteRule (.*) /some/page/%1? [L,R=301]

Hope this can help.