https://github.com/EightBitz/RWImport
Please read the readme. Do not consider this a finished product.
Backup your database. Make copies of your realms. This is only lightly tested, and in a limited environment. I can't guarantee anything if you run this code. I have run it several times on my own system, but I've only ever imported into empty realms, never populated ones.
I'm mainly sharing this for those who have asked to see my process. Be safe and be cautious.
And read the readme.