Thanks for contacting the community. You should be able to sync your Documents folder under Shared, it's just a matter of having permissions and changing the command line commands. The 2nd question though where you can sync your private to shared, unfortunately, that would have to be a no. Use-case wise we generally never see anyone link their folders to /Shared, the reason being is if mishandled in permissions, other users can see your contents or even modify/delete them. If you need further assistance, we recommend you contact support at firstname.lastname@example.org.