You can use the MD600 as the NAS for a Roon library but it would not be my choice. I would still export the Sooloos library although I believe Roon can read the Sooloos files but it restricts what Roon is able to do so it is not recommended, then copy it back to the drives on the MD600.

The MD600 just shows on the network as a disk like any other disk would then you just drag and drop the files.

Russ