Time machine migration

Hi, I have a WD MyBook Studio that I have been using for time machine backups of multiple machines. It’s full and I’d like to migrate my old backups to the new MBLD. Has anyone done this before? What are the steps?

I had one thought where I could create shares for each machine then copy over the time machine backups and use tmutil to reassociate.

That seems redundant though since supposedly MBLD has time machine support built-in. I don’t see anyway of managing it directly without doing a backup first.

Is there something else I can do? I’m not afraid of commandline.

Thank you

The steps on the link below are for a USB hard drive, but they should also work for a NAS.