Only transfer snapshots

How can I only transfer snapshots without creating new ones? I could use btrbk archive for that, but I try to integrate it into my central btrbk.conf.

The scenario is like this:

I have several machines. Each machine has a local data store. Then I have a mobile data store that I carry with from machine to machine. The mobile data store is the central store which will have all snapshots from all machines.
Each machine should send its snapshots to its own local datastore and also to the mobile datastore, if currently available. Each machine will also try to reach other machines to copy snapshots from them.
Now I added the **section "Reverse Backups"** in order to copy snapshots from mobile datastore back to the local datastore for backup duplication.

For instance. the attached example btrbk.conf is from desktop_one. It will send its snapshots to local and also mobile. It also tries to reach other machines like laptop_one, server_one and laptop_two, if available. It will also send their snapshots to the mobile datastore, but also to some archive dir on its local datastore. Because some machines don't see each other or only see each other online only infrequently, the machine should try to find snapshots from the central mobile datastore and copy them back to the local datastore.

I tried to follow the example https://github.com/digint/btrbk#example-multiple-btrbk-instances because this only sends without changing the source. But it seems I always need to reference the original subvolume of the snapshot. That doesn't work in my situation.
Being on desktop_one it should copy snapshot of desktop_two back from mobile to local, I have no access the the original subvolume at that time.

Is btrbk archive the only way to do that?

[btrbk-public.conf.txt](https://github.com/digint/btrbk/files/12740906/btrbk-public.conf.txt)

btw. laptop_two is an OpenSuse machine, btrbk is adapting to the co-existing Snapper scheme there.

Start with the linked multiple-btrbk-instances example and the attached btrbk-public.conf.txt, focusing on the “Reverse Backups” section and the archive configuration. Check whether the existing configuration can transfer snapshots from the mobile datastore without access to the original subvolume. Done means establishing whether this is supported and documenting the required central btrbk.conf configuration or confirming that archive is the only supported approach.

Written by the indexing model from the issue text.