Sharing files query for new team

I've updated all our designers from very old versions of the product to the new Cloud offerings, one of the main reasons for this was the opportunities it offers for  collaboration.  However, its not being widely used.   Reason being that they like to keep all the creatives in one place i.e. the traditional windows file server using a directory for each client.  No-one really holds creatives locally.

The cloud sharing looks to be a 'OneDrive' type experience wherein a local drive is sync'd to your cloud account and from there you can share files or groups of files with other users.  This is fine itself BUT they don't want individuals to effectively own any files i.e. be the ones that hold the local copy, they want one big shared area that they can all access such as currently happens from the file server.  No-one needs to be holding a local copy.

How can I set things up for the team so that they can work in such a manner?

Thanks