[flexcoders] XML Filtering

[markgoldin_2000]

For this simple XML:
<root>
  <data>
   <filter>f1</filter>
   <value>1</value>
  </data>
  <data>
   <filter>f1</filter>
   <value>2</value>
  </data>
  <data>
   <filter>f2</filter>
   <value>3</value>
  </data>
</root>
is it possible to retrieve unique values of an element "filter"?

Thanks