Branch environment flow for Terraform Cloud

First of all, this is my first post here so sorry if I’m violating any convention.

I exploring the parity between GitLab Repo branches and Terraform Cloud Workspace as a development/release flow.
It’s not complicated and it’s all based on promoting changes (dev → stage → production) by using PR/MRs.
However, I couldn’t find a way to enforce that certain branches can only accept PRs from certain others.
How can I make sure that you can create PRs to the production branch ONLY from the stage branch?
Is there anything like that?