The link below may be of help
Those with site role of Explorer have certain capabilities......
You could use a permissions rule to define who is allowed to work on a project, workbook, view or data source. More details below, hope this helps...
Add project based permission and set who all are having publish access and give one project folder. Restrict to other folders too.
If they publish from machine then the people able to see only their permission added project folders. so they can save their workbook in that folder only.
Thanks a lot for the answers!
You're welcome Andreas