What is the correct Nextcloud sync for high volumes?

Question

ownCloud/Nextcloud

We set up a common nextcloud for the company with a breakdown into groups (access to files of a certain group), etc.
However, such a question arose. Many users put themselves on the PC access via webdav, ie. throw the file into a folder and it is synchronized with the server.
The problem is that they also want to see the files of the group in this folder, but not to clog their hard drive.
Is it really possible to do this at all?
well, i.e. now mycloud is working external hard, it is added as an ip to the system and all folders on it, without local saving on the user's PC