title: Mercurial Merging only certain changesets
body: <p>Ok, so we recently converted from SVN to Mercurial.<br />
  We are using TortoiseHG normally.<br /><br/>
  In our one repository we have all of our projects, C++ / .NET / ASP. We have about 100 projects, all using common library projects.<br />
  <br />
  So it would be quite difficult task to create multiple repo's for each project. <Br/>
  <br />
  Now, we have the <code>default</code> branch, and let's say <code>branchA</code>. <br/>
  I'm working on <code>BranchA</code> and adding my uber changes to it, and I change a common library, let's say an extension method<br /></p>
  
  <p>I want to commit this to <code>branchA</code> and <code>default</code>, how would I go about this? <br/></p>
  
  <p>However, I don't want all my changes from <code>branchA</code> to be merged into <code>default</code>, and I don't want all the other changes from <code>default</code><br /></p>
  
  <p>Hopefully this is sufficient information!</p>