Domain attached to category
The way my forum is setup, I have many categories and need to have a few of those categories act like their own site with their own domain name. For instance I would like "myforum.com/categories/example" be available from "example.com." Right now I have my domains forwarded to their respective categories where the url displays as "myforum.com/categories/example" after the user enters "example.com."
I would instead like the user to browse strictly in "example.com" except when leaving that category or going back to the site index. So basically that category needs to act as if it is its own vanilla installation with a mutual database with the main site. I do not however what to maintain multiple vanilla installations. My forum uses the Anonymouse plugin and therefore does not utilize any type of user accounts (if that makes doing this any easier).
I have done much research about this and it is easy enough to do with .htaccess when there is a physical subdirectory within the root directory. However I have not figured out how to make this work when there is no physical subdirectories to point to, such as the case here.
If anyone has done this on their own site or is an .htaccess expert, any help would be much appreciated.
Also, a similar situation would be if someone were to try and implement a subdomain for each category.