title: Git config with directory scope, containing multiple repositories
body: <p>The situation is as follows:</p>
  
  <ul>
  <li>I have multiple <em>domains</em> in which I write code, e.g. professional and free time. Those are represented by different directories on my computer.</li>
  <li>Each of those domains contains multiple Git repositories, in a hierarchical directory structure inside one of the domain directories.</li>
  </ul>
  
  <p>Per domain, I want to use a different email address as part of author/committer information. That is, I want my private address to be listed in my free-time projects and my company address in my professional ones.</p>
  
  <p><code>git config</code> knows 3 scopes: repository, global and system-wide. <strong>What I basically need is a 4th scope between repository and global, representing a group of repositories (or simply a directory in the file system).</strong></p>
  
  <p>It seems like <code>git config</code> doesn't allow that. Of course I could set the email address per repository, but I want to avoid this manual step every time I set up or clone a repository. One option would be to write a script that wraps <code>git init/clone</code> and <code>git config</code>, are there other ideas?</p>