Ignore site ISAPI rewrites

So, I'm at work. and i have a problem. We have 40 odd sites using the same rewrite rule sheet how do you stop the sites using the wrong rewrites?

This had me stumped. I was looking through documentation, and looking at forums for help and couldn't find a thing. So i thought screw it let me try this!...

RewriteCond  Host:  www.mydomain.com
RewriteRule (.*) $1 [I,U,L] 

Well it worked.
I managed to get the page to keep the folders and everything and not be re written!!
Try it out... you'll love it!