Some complicated projects are setup across many repositories and it can be both cumbersome and error-inducing to manually submit and merge Pull Requests(PR). Somehow allowing for a single entry point for PRs at a project level would be a huge boon for larger projects.
-When a PR is created, check to see if PR should also be created in other repositories of project.
-When merging, merge related PRs in project.
Other systems enforce same branch name for linking PRs together. Obviously only checking for open PRs, not closed, nor merged.