@DJ Herman > I'm not sure how you use Rekordbox on a cell phone. ;) lol I think you meant you export your analyzed tracks to your phone?
Sorry but I do not believe there is a way for you to be able to access both drives because the CDJ's only recognize the first partition or "drive" on a device. If you would like to use both sources, you will need to pick up an adapter to plug the MicroSD card into the SD card slot on the CDJ-2000. Then you will need to switch between the sources depending on which drive the track is located on.
I hope this is helpful. :)