Default reviewers required when merging all branches except one

We have a repository with a Gitflow branching model: the default branch, develop, is where developers integrate their changes. The release branch is where those changes are stabilized before release. The master branch represents what's been deployed live.

Members of our QA and Release Management team are required to approve all pull requests into the release and master branches. However, Release Management doesn't care what gets promoted from the develop branch into the release branch.

So, we'd like to be able to say, when setting up default reviewers, that Release Management is required except when merging a specific branch.