How to stop a Sharepoint library syncing down to PC via OneDrive

Hi there

The way we use Sharepoint Online from Office 365 as company's file server is not using OneDrive sync type of approach.  We used the WebDAV approach by mapping out the drive. As we have many Sharepoint document library, we mapped the drive accordingly ie. Marketing, HR, IT etc. However, for typical on-off project-based, we allowed the user to use OneDrive.

The challenge though when the user login to Sharepoint via web. If the user to go the departmental document library, the user is able to "Share this" with user's OneDrive. Is there any way that we can stop this by any chance at the site level or sub-site level?

As our Sharepoint sites/sub-sites hierarchy as follows:

1. Marketing
2. Business Development
3. HR
4. Accounts
5. IT
6. Projects
   1. Project A
   2. Project B 
   3. Project C

I'm appreciated your help.