title: combining unrelated git repositories retaining history/branches
body: <p>we're having 3 separate git repositories (each with some branches) which we'd like to combine into one keeping full history and the ability to access the branches, like so:</p>
  
  <p>so this is what we have. 3 repos:</p>
  
  <pre><code>/A/.git
  /B/.git
  /C/.git
  </code></pre>
  
  <p>and we'd like to have one super-repo with 3 subdirectories:</p>
  
  <pre><code>super/.git
  super/A
  super/B
  super/C
  </code></pre>
  
  <p>and say when switching to branch feature1 (which was originally in repo B, introduced at a time that repo C didn't exist yet) we'd expect the result to be:</p>
  
  <pre><code>super/.git
  super/A
  super/B
  </code></pre>
  
  <p>we've read <a href="https://stackoverflow.com/questions/277029/combining-multiple-git-repositories">Combining multiple git repositories</a> but had troubles using git-stitch-repo which basically worked as advertised only that quite a large number of commits were missing in the super-repo (without any error messages that would point to a problem). </p>
  
  <p>any idea what we could be doing wrong here?</p>
  
  <p><strong>EDIT</strong>
  we are aware of submodules and subtree-merging, but both are not an option. this is supposed to be a one time operation. we need the repos joined once and forever. </p>
  
  <p><strong>EDIT</strong>
  probably a simpler way to put basically the same question: say we have one repo with 3 totally unrelated branches. we can merge them without a conflict to one branch (since they share no files). now when looking at the history we see 3 unrelated branches of commits and the one point where they come together. but what we'd like to see is one branch made up of the interleaved (by date/time) commits of all 3 branches. </p>