title: Mercurial repo: ignore all folders which contain their own repo?
body: <p>I came on board about 6 months ago, and when I arrived, my group was using NO form of versioning.  I have since convinced mgmt to use Mercurial in new projects, so we have on our webserver the following structure:</p>
  
  <pre><code>-MainFolder (which includes files for the main project)
    +Subfolder A, which contains (old) project A with NO hg repo
    +Subfolder B, which contains (old) project B with NO hg repo
    +Subfolder C, which contains (NEW) project C AND a hg repo
    +Subfolder D, which contains (NEW) project D AND a hg repo
  </code></pre>
  
  <p>Note that the only folders which currently have a repo are subfolders C and D, which represent seperate projects.</p>
  
  <p>I would like to add a repo to track everything which is currently not tracked, but want to ignore the folders which currently have their own repositories.  I know about using <code>.hgignore</code> files, but from what I understand that would require me to explicitly ignore every folder which contains a repo.  This isn't a problem in the above example (with only two existing repos), but our actual setup has more projects than this.</p>
  
  <p>Is there any way to tell Mercurial to dynamically ignore all folders which have a repo in them, and track everything else?</p>