Server that can share a DropBox account with granular permissions?

Hi Everyone, I hope I put this in the right category.

So I’m in the middle of setting up a new TrueNAS server for a client. It’s for a video editing workflow for editing blackmagic 6k and 8k footage.

We were setting up the dropbox account on it and it seems I’m not able to create specific share permissions for folders in the dropbox account.

The idea was to be able to have people editing off the DropBox account thats is on the server and then it synching in the evening but we don’t want to give each user full access to all the folders in the shared dropbox on the server.

Is there a setting I’m missing in TrueNAS or is it just not possible the way I want to run it. I’m open to exploring other operating systems but would prefer to stay with a ZFS based system with easy web UI.