Deploy to multiple production environments

** Please describe which feature you have a question about? **
Amplify

** Provide additional details**
I have a blog-like site I built for my wife and me using Amplify. I set up two environments for this (including backends). Now I want to set up a development environment so I'm not editing production data during development. Ideally, I'd like to develop on dev, and somehow (using Functions or something?) deploy dev to those two production environments when it's ready.

My roadblocks are:
- Amplify only allows one Production Branch for an app, but I think I need 2 (one for her site, one for mine)
- I'm not sure how to automatically update the two production branches when I push to dev
- E.C. How do I rename an environment without losing all of it's data? Her site is on master, but obviously that makes no sense. I would delete it and create a new one, but I'm worried I'll lose all her data, which has already happened once before.

Maybe I've got all this wrong and I should actually have 2 Amplify apps? One for each of our websites and then a dev environment on one of the apps? In this case, I will need help migrating all the data of one of our sites.

I'd appreciate some guidance.

Start with Amplify's documented production-branch and environment model, then compare it with the two-site, development-to-production workflow described here. Determine whether separate Amplify apps or environments fit, and verify a migration path that preserves existing data. Done means a documented, safe deployment and rename plan.

Written by the indexing model from the issue text.