title: Merging configuration values in Maven
body: <p>I have a Maven submodule which needs to append a string to the existing value of a configuration option. The parent module looks like this:</p>
  
  <pre><code>&lt;!-- in parent --&gt;
  &lt;plugin&gt;
     ...
     &lt;configuration&gt;
         &lt;someOption&gt;A&lt;/someOption&gt;
     &lt;/configuration&gt;
     ...
  &lt;/plugin&gt;
  </code></pre>
  
  <p>The submodule needs to append a string to <code>someOption</code>, such that the effect is as if the submodule has done</p>
  
  <pre><code>&lt;!-- in child --&gt;
  &lt;plugin&gt;
     ...
     &lt;configuration&gt;
         &lt;someOption&gt;A B&lt;/someOption&gt;
     &lt;/configuration&gt;
     ...
  &lt;/plugin&gt;
  </code></pre>
  
  <p>I've looked at the <code>combine.*</code> attributes, but none of them seems to do what I want. Is there a way to do this? Would it be possible to access the parent's value of <code>someOption</code> from the child?</p>