This question has been answered by leif.hjerpe. See the first response.
☆ A M B ☆
# Establish site root
RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^assets\.
RewriteCond %{HTTP_HOST} !^mail\.
RewriteCond %{HTTP_HOST} !^operations\.
RewriteCond %{HTTP_HOST} !^www\.
RewriteRule ^(.*)$ http://www.PRIMARY-DOMAIN.com/$1 [R=301,L]
# The Friendly URLs part
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]
☆ A M B ☆
RewriteCond %{HTTP_HOST} !^assets\.
RewriteCond %{HTTP_HOST} !^mail\.
RewriteCond %{HTTP_HOST} !^operations\.
RewriteCond %{HTTP_HOST} !^www\.
if ($host ~ ^(?!(assets|mail|operations|www)\.)) {
rewrite ^ $scheme://www.PRIMARY-DOMAIN.com$uri permanent;
}
location / {
try_files $uri $uri/ @modx-rewrite;
}
# rewrite js, css and media requests for some.domain.com
if ($host ~* ^some.domain.com) {
rewrite ^/(js|css|media)/(.*)$ /somedomain/$1/$2 last;}
location /
{try_files $uri $uri/ @modx-rewrite;}
}
Based on this I made my own:
# rewrite css|drive|im|js|media requests for vision.portraits.se
if ($host ~* ^vision.portraits.se)
{rewrite ^/(css|drive|im|js|media)/(.*)$ /2.vision/$1/$2 last;}
# rewrite css|drive|im|js|media requests for my.xnova.se
if ($host ~* ^my.xnova.se)
{rewrite ^/(css|drive|im|js|media)/(.*)$ /3.my/$1/$2 last;}
# rewrite css|drive|im|js|media for guide.xnova.se
if ($host ~* ^guide.xnova.se)
{rewrite ^/(css|drive|im|js|media)/(.*)$ /0.guide/$1/$2 last;}
# rewrite css|drive|im|js|media requests for demo.xnova.se
if ($host ~* ^demo.xnova.se)
{rewrite ^/(css|drive|im|js|media)/(.*)$ /1.rikt/$1/$2 last;}
# test bed for publishing following domain:
# rewrite css|drive|im|js|media requests for rikt.se
#if ($host ~* ^rikt.se)
#{rewrite ^/(css|drive|im|js|media)/(.*)$ /1.rikt/$1/$2 last;}
location /
{try_files $uri $uri/ @modx-rewrite;}
}