OT: Apache .htaccess question

[Ashley M. Kirchner]

Looking for some gurus here.  I have the following snippet in my 
.htaccess file:

SetEnvIfNoCase Remote_Host "some.domain.com" ref_ok=1
<FilesMatch ".(gif|jpe?g|png|css|inc|GIF|JPE?G|PNG|CSS|INC|js)">
  Order allow,deny
  Allow from env=ref_ok
</FilesMatch>

...which effectively prevents anyone from remote linking to any of 
those files anywhere on my web site (including those in sub-directories) 
except for 'some.domain.com'.  However, I want to _exclude_ a directory 
from that blanket matching:

$web-soot/.htaccess
    $web-root/thx/         <-- I want to exclude this directory and
                               everything else that may be below it.

Any ideas?