Xquery to Eliminate a particular value in the response

Hi ,
I am new to SOAP UI. I have a query regarding the xquery. I am trying to automate webservices using REST through soap UI.I am adding an assertion as follows using xquery and generating the expected result.

/response

This retrieves the following


<tag-groups>
<tag-group>
<name>SCIENCE_FICTION</name>
<tags>
<tag>
<name>he Death of a Legend</name>
<timeStamp>1297164529013</timeStamp>
<author>Robert Adams</author>
</tag>
<tag>
<name>The Castle of Llyr </name>
<timeStamp>1298353298369</timeStamp>
<author>Lloyd Alexander</author>
</tag>
</tags>
</tag-group>
<tag-group>
<name>THRILLER</name>
<tags>
<tag>
<name>The Graveyard Shift</name>
<timeStamp>1297164958318</timeStamp>
<value>Jack Higgins</value>
</tag>
</tags>
</tag-group>
</tag-groups>
</response>


From this response i don't want the tool to check for the timestamp value in the actual result.Please let me know if this is possible..