External Storage Viewable By All Users [Noob Question]


I recently just loaded NextCloud onto my server and am very new with it.
I’m planning to use it to host partner and client files etc.
Is it normal for all users to be able to see into the External Storage I have set up in AWS S3?
I’m hoping I can just hide that and they not really know where the files are being saved, or be able to go through other companies files.

I read that I can set up other External Storages which I could do, but if possible I’d like to have as few as possible and only share the files needed to the respective companies/partners.

Is this possible?

Thank You