How to automatically unsync Shared files/folders?

Hello Community,

We have deployed a Nextcloud 18 server associated with Desktop sync clients 3.0.x for Windows, Mac and Linux in our organisation.
First we focus the File sync as primary feature for users local file backup solution that works well!
We are planning to open now the share feature and firsts tests seems to be ok, but we are facing and unexpected behavior that can make an no-go : When a user (aka user1) shares a file or folder to another user (aka user2), shared files/folders is automatically synced locally on user2’s HDD.
If users share little files and don’t use the feature so much, it won’t be a problem, but we think (we know) that users will use share for many type of purpose and may shares big files/folders that can saturate local HDD free spaces of colleagues.
So the question is : is it possible to not sync files/folders shares with you ?
I don’t find the answer yet, but I really need to know before choose to put that feature in production!
Nota : For test I’m using a old test server in 13.0.4 with 3.0.3 sync clients
Thanks in advance.