WordPress mod_rewrite is canceling/overwriting my other mod_rewrite rule

in /www/ I have an .htaccess file containing:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^([^.]*.less)$ compilers/lessphp.php?file=$1 [R,QSA,L]
</ifModule>

This code works fine, until I’m requesting .less files in /www/blog/, where WordPress is located, and has its own .htaccess file which contains the standard pretty permalinks mod_rewrite:

<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /blog/
    RewriteRule ^index.php$ - [L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /blog/index.php [L]
</IfModule>

If I move WordPress’s mod_rewrite code to the root, and place it before my own mod_rewrite, everything works as expected:

# BEGIN WordPress
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /blog/
    RewriteRule ^index.php$ - [L]
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule . /blog/index.php [L]
</IfModule>
# END WordPress

# BEGIN LESSPHP
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteBase /
    RewriteRule ^([^.]*.less)$ compilers/lessphp.php?file=$1 [R,QSA,L]
</ifModule>
# END LESSPHP

The annoyance here, is any modification in WordPress to do with permalinks means I need to remember to cut the .htaccess code from /www/blog/ and move it to the root.

Is there any way I can improve upon my mod_rewrite so WordPress isn’t overwriting it, and I can just leave everything where it is naturally placed? I would also rather not need to have two instances of my rule in both root and after WordPress’s. Also, WordPress’s mod_rewrite rules should be altered, since updating permalink settings will simply overwrite them.