Exceptions for certain sub-domains

We are building a BuddyPress/Multi-Site install and are using sub-domains for the member-created blogs. There are a few blogs that we the admins are creating for the site, and for navigation purposes we would rather have those blogs' addresses be sub-directories - i.e., for our own blogs instead of...

exception.domain.com

...we'd like the address to be ...

domain.com/exception

I figure there must be something we can put in the root .htaccess file that would essentially override the subdomain code and change the addresses for these specific exceptions; but I don't know what that code is. Can anyone help me here? Thanks in advance --