Mixed storage: S3 and local storage depending on uploader

Is it possible to mix storage methods? I have some uploader storing files in FileSystem at the moment, and I’d like to migrate it to S3 later, but not all at once. My testing so far has been to remove the storages declaration from the Shrine initializer, and to set it within the subclasses, with storages = { … }, rather than the initializer, which uses Shrine.uploaders = { … }.

When I try to upload using the S3-backed uploader in local development mode, I get a weird error that indicates that the upload is trying to go to my filesystem, not S3. The local storage uploader still seems to work.

Is this expected to work, and I’ve messed up the configuration, or is there an expectation that all uploads in a single Rails application will share one Shrine parent class, with one storage protocol?