The leverage available to you depends a lot on the actual path names themselves.
For example:
I keep my audio files in [file type] parents. So, i have things like D:\Music\ape\Bob Dylan\Hard Rain\ and D:\Music\flac\Bob Dylan\Street Legal\
The following rule when entered into Step 4 of the edit view scheme dialogue excludes all ape files except for a single Marc Cohn album that I know is in the \ape\ directory.
[media type]=audio -[=isequal([filename (path)],\ape,8)]=1 or [=isequal([filename (path)],marc,8)]=1
It says: Give me all audio, but exclude any files that have \ape in their path name, or, also show me files that have marc in the path name. I get all audio, excluding ape files, except for those marc cohn files.
The ,8 that follows the string to compare tells MC to make a case-insensitive, sub-string search, or in other words, the question you're asking is not "does the field equal this?", but rather "does the field contain this?"
Not knowing your exact directory structure, I can't offer a lot more help than that, but hopefully, there's enough there to get you rolling. This method would mean you would have absolutely no access to the excluded files in this view scheme, Datdudes suggestion would make them available under the "All" entry, with the option of filtering them out via selections made within the pane itself.
-marko.