XML Handling using X-path using Java/groovy script - groovy

Question

I have a very deep/nested structure xml where I need to filter only those fields which will be declared in some store(parameter let's say). Or the other solution is , I need to make those field values as "X" which are not stored in the parameters. As the structure is very deep, I suppose the field should be declared in the parameter as x-path.
Please suggest some clues.
I am using the below code now but this is removing all the fields under different nodes as well. I want to remove this from a particular node. For example(as shown below) field 'action' is present in many nodes but I want to remove this from some specific nodes.
Or I want to set this field value as "X".
def xml = new XmlParser().parseText(body)
def nodes = xml.'**'.findAll{ node -> node.name() == 'action' }
//nodes.each{it.text()}
def removeNode = { node ->
def parent = node.parent()
parent.remove(node)
}
nodes.each{removeNode(it)}
def final_body = groovy.xml.XmlUtil.serialize(xml);
My input data is as follows:
<?xml version='1.0' encoding='UTF-8'?>
<query>
<Emp>
<id>34032</id>
<ps>
<action>INSERT</action>
<id>34032</id>
<PI>
<action>INSERT</action>
<gen>M</gen>
<ms>S</ms>
<PI_mex>
<action>INSERT</action>
<genericNumber1>0</genericNumber1>
<genericNumber2>0</genericNumber2>
<genericNumber3>0</genericNumber3>
<genericNumber4>0</genericNumber4>
<genericNumber5>0</genericNumber5>
<genericNumber6>0</genericNumber6>
<genericNumber7>0</genericNumber7>
</PI_mex>
</PI>
<PI>
<action>INSERT</action>
<gen>M</gen>
<ms>S</ms>
<PI_mex>
<action>INSERT</action>
<genericNumber1>0</genericNumber1>
<genericNumber2>0</genericNumber2>
<genericNumber3>0</genericNumber3>
<genericNumber4>0</genericNumber4>
<genericNumber5>0</genericNumber5>
<genericNumber6>0</genericNumber6>
<genericNumber7>0</genericNumber7>
</PI_mex>
</PI>
<ai>
<action>INSERT</action>
<city>SAN NICOALAS DE LOS GARZA</city>
<country>MEX</country>
<state>NLE</state>
<zip_code>66420</zip_code>
</ai>
<ai>
<action>INSERT</action>
<city>SAN NICOALAS DE LOS GARZA</city>
<country>MEX</country>
<state>NLE</state>
<zip_code>66420</zip_code>
</ai>
<ei>
<action>INSERT</action>
<id>26658</id>
<user_id>00860884</user_id>
<ji>
<action>INSERT</action>
<c_string10>5</c_string10>
<c_string11>P</c_string11>
<c_string12>MX_F_1E</c_string12>
</ji>
<ji>
<action>INSERT</action>
<c_string10>5</c_string10>
<c_string11>P</c_string11>
<c_string12>MX_F_1E</c_string12>
<c_string13>1310</c_string13>
<c_string16>90000269</c_string16>
<c_string17>Y</c_string17>
<c_string18>BCC</c_string18>
</ji>
<CI>
<action>INSERT</action>
<pg>M9</pg>
<pr>
<action>INSERT</action>
<pc>GL1003</pc>
<pc_type>AMOUNT</pc_type>
</pr>
</CI>
</ps>
</Emp>
</query>
Thanks.