Hi HAZCHEM,
We are not aware of such a switch, even for AutoCAD 2015. Command Line Switch Reference:
https://knowledge.autodesk.com/support/autocad/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/AutoCAD-Core/files/GUID-8E54B6EC-5B52-4F62-B7FC-0D4E1EDF093A-htm.htmlThat is because read/write privileges are normally set by the operating system, not by the application.
If the file is on a Windows PC, for example, you can usually adjust read/write privileges for specific users or groups in File Explorer right-mouse clicking on the file (or the entire folder) and selecting "Properties" -> "Security" tab.
The exact procedure and functionality may differ between windows versions, and you would need to speak to your Microsoft consultant or IT dept for what is correct on your operating system version.
Please let us know if this solves the issue for you or if your requirements can't be met this way..