What do you mean with "_DIRECTORY only reads data from the tags in the files themselves"?
_DIRECTORY does not read any tags, it's only the folder name.
You can't combine web sources and actions in a group which runs automatic. And you can't write _DIRECTORY or _FILENAME with web sources.
But there is of course a simple action for you which you can run after you have tagged your files with one of the discogs web scripts:
Action: Format Value
Formatstring: %artist% - %album% '['%year%']' '['%country%']' '['%genre%']'
Maybe you should use %albumartist% instead of %artist%, but that's up to you.
And maybe you need %discogs_country% instead of %country%, that depends on the scipt you are using.