Redirect control from WP to Magento for specific subdomains

I have a mutisite subdomain install. I have had issues with using wildcard subdomains and trying to install Magento on a specific subdomain on MediaTemple

See This: http://wordpress.org/support/topic/override-wildcard-sub-domains-on-wp-multisite-mediatemple-dv?replies=4

I want to use WP Multisite to run specific subdomains while other OSS software like Magento run other specific subdomains. The wildcard subdomains prevent this and my virtual host attempts failed to overide it. My solution is to define which specific subdoamins WP sholud run and leave all others alone. This has brought an issue so I realize its not the best solution.

1. How do I specify in my .htaccess that;
If HTTP_POST (or suggest a better server variable) says request is from shopping subdomain redirect to the shopping DocumentRoot where Magento is installed so Magento runs that request.

Will this work for ensuring requests to the shopping subdomain are not handled by WP but by whatever is in its documentroot.

Note: There is a physical subdomain for shopping not virtual

2. Do you see any conflicts between Magento and WP in such a situation