More disk and space

I do not want to put this

hello I have a server nextcloud and the question that I ask myself is that it is possible to put at the root of the file the choice between all my disk
do it at the root of the admin file there is

Disc 1
Disc 2
Disc 3

So you want to put user1 and user2 on disk 1, user 3 on disk 2, …? You want to do this as an admin, or even give each user a choice?
Both things are not easily doable, perhaps you can hack around that. There is for example a group folder-app (a separate space where groups can share files). So perhaps you can use that to make your own app.

There is perhaps one way, you create users and for each user you can give an external storage (which can be any folder in the filesystem where the webserver user has access) for each of the disks.