I have a main repository and a fork repository managed in a GitHub-like SCM system. Now I've migrated both repositories to GitHub by creating two repos main and fork in GitHub, added them as remotes to my local repos and pushed the entire history to both of them. So far, so good.

When I would have forked fork from main directly on GitHub fork would be marked as such on the GitHub UI.

My question is, can I connect the repositories in GitHub somehow such that they appear as if forked on GitHub?