diff --git a/usr/local/sbin/restic_backup.sh b/usr/local/sbin/restic_backup.sh
index d79fe09..1f5aac2 100644
--- a/usr/local/sbin/restic_backup.sh
+++ b/usr/local/sbin/restic_backup.sh
@@ -63,8 +63,10 @@ wait $!
 
 # Dereference old backups.
 # See restic-forget(1) or http://restic.readthedocs.io/en/latest/060_forget.html
+# --group-by only the tag and path, and not by hostname. This is because I create a B2 Bucket per host, and if this hostname accidentially change some time, there would now be multiple backup sets.
 restic forget \
 	--tag $BACKUP_TAG \
+	--group-by "paths,tags" \
 	--keep-daily $RETENTION_DAYS \
 	--keep-weekly $RETENTION_WEEKS \
 	--keep-monthly $RETENTION_MONTHS \