copy a barman snapshot to another backup server

We also have an off-site backup server in another city that always holds 1 backup snapshot of all servers, to protect the data in case of a fire or natural disaster. But i haven't included the barman backups in that yet.

What would be the best way to pull a snapshot from barman?

The snapshots are pulled by the off-site server using rsync; we have no access from on-site to off-site. So what I'd do is restore a backup locally on the on-site backup server and backup that from off-site.

That would be wasting some space and IO though, a snapshot is about 1TB. Is there a more efficient way? E.g, i was hoping to somehow hardlink the local restore, but i haven't found a way yet.

Cheers,