Do you think we should add the SACD layer separately if it shares the same recordings?
In such cases we can just have a single Hybrid SACD medium, IMO, with DiscID.
But if you want to create a second medium with same recordings, you can edit the release and, in Tracklists tab, click Add medium: Existing medium and find and use the first medium by searching the same album by filling out artist, album name and track count.