C# regex to get all complete xml nodes (except few ones) with all its attribute and its value

Question

Sample XML string is here :

<test name="Regression1">
  <groups>  
    <define name="all">
      <include name="functest"/>
      <tina title="manager">dummyTag</tina>
    </define>
  </groups>  
  <classes>
   <tina title="client"/>
    <class name="test.sample.Test1"/>
  </classes>
  <demo>dummyTag</demo>
</test>

I want a c# regex which can find any tag other than (test,groups,define,include,classes and class) with its all attributes and value if any.

I am expecting result :

<tina title="manager">dummyTag</tina>
<tina title="client"/>
<demo>dummyTag</demo>

result nodes can be self closed or normal close tag. Thank you in advance