title: how to find all links at the same depth with a common closest ancestor with nokogiri
body: <pre><code>d=&lt;&lt;"EOM"
  &lt;ul&gt;
    &lt;li&gt;&lt;a id=t href="t"&gt;a&lt;/a&gt;&lt;/li&gt;
    &lt;li&gt;&lt;a id=b href="b"&gt;b&lt;/a&gt;&lt;/li&gt;
    &lt;li&gt;
      &lt;ul&gt;
        &lt;li&gt;&lt;a href="inner"&gt;don't want inner&lt;/a&gt;&lt;/li&gt;
        &lt;li&gt;&lt;a href="inner"&gt;don't want inner&lt;/a&gt;&lt;/li&gt;
      &lt;/ul&gt;
    &lt;/li&gt;
    &lt;li&gt;&lt;a id=c href="c"&gt;c&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  &lt;ul&gt;
    &lt;li&gt;&lt;a href="d"&gt;don't want&lt;/a&gt;&lt;/li&gt;
  &lt;/ul&gt;
  EOM
  
  doc = Nokogiri.HTML(d)
  t = doc.css("#t")[0]
  </code></pre>
  
  <p>how can i get all hrefs that have the same 
  outer container as "t" and are at the same
  <em>depth</em> as "t"?  in this case i'd want just the
  hrefs t,b,c.
  these will not always be in ul's, just using
  it as an example.</p>