Ok, thanks for the clarification @allineedis – it should work in either way, but you’ll have to pick one 
the default behavior will be based on how you have the files stored on your drive, and what their tags look like.
For example, if Disc 2 is in its own folder, with file tags that mention album title “The Freewheelin’ Bob Dylan” and media number as “Disc 1 of 1”, we’ll almost certainly identify it as the original release.
Alternatively, if it’s in a folder called “Disc 2” with tags that say “Complete Album Collection” " and “Disc 2 of 47” we’re likely to identify it as part of the set.
The one thing we don’t really support is a single folder with 500-odd sequentially numbered tracks, as mentioned by @jeremiah here.
We have heard some requests for greater level of detail at the disc level in multidisc sets – different cover art per disc, or disc titles. We’re considering these requests for a future release, but right now, metadata for multi-disc sets is at the album level (other than track based info like title, credits, etc).
Our editing tools can help in the case you mentioned, as you could use our track grouping feature to divide a set into the original albums, or vice versa. You could also use our Identify feature to match up albums to either the full set, or the original releases. I’m looking into how our editing tools do when the sets are as big as this – I’m guessing there may be some issues, so right now it may be more expedient to make the changes to your files based on how you want them to show up in Roon.
I’m looking into this set more specifically now, so stand by for some more specific feedback. For now, let me know if that all makes sense.