Override group name 2 character limit

Hello, I am trying to port to heptapod (GitLab fork for mercurial) from Kallithea. We have several groups with single letter names and I am required to keep the paths the same, but GitLab added a 2 character minimum restriction about a year ago (Require username/namespace to be at least 2 characters long (#225214) · Issues · GitLab.org / GitLab · GitLab). Is there a way to override this?

Almost all of our repos have externals (like git submodules) that point to other repos that have single character named groups. Changing single letter groups to 2 letter groups will prevent us from pulling an earlier commit that has a subrepo that points to the single letter version.