how can I deal with the xml problems

Hello dear firend:

I have a question here ,could you kind enough to give me a quick answer

fellowship:
<?xml version="1.0" ?>
- <fellowship id="1000">
  <title>Entertainment Club</title>
  <descr>welcome to this amazing club</descr>
- <members>
- <member id="200201">
  <link url="file:// wangning" />
  </member>
- <member id="200202">
  <link url="file://Derek" />
  </member>
  </members>
  </fellowship>

and the other two have the same structure one is fellow1.xml

<?xml version="1.0" ?>
<fellow>
  <name>Ning</name>
  <surname>Wang</surname>
  <email>ilydear@xxxxxxxxxxx</email>
 <resources>
 <resource id="001" type="mp3">
  <title>Hero</title>
  <author id="Sony">John</author>
  <description>Famous in UK.</description>
  <location url="file://wangning" />
  </resource>
 <resource id="002" type="mp3">
  <title>Titanic</title>
  <author id="BMW">Jane</author>
  <description>Famous in World!.</description>
  <location url="file://wangning" />
  </resource>
  </resources>
  </fellow>

and fellow2.xml

<?xml version="1.0" ?>
- <fellow>
  <name>Derek</name>
  <surname>Ben</surname>
  <email>derek@xxxxxxxxxxx</email>
- <resources>
- <resource id="003" type="ebook">
  <title>Ghost</title>
  <author id="UK">TomJohson</author>
  <description>Written in 1978.</description>
  <location url="file://Derek" />
  </resource>
- <resource id="004" type="ebook">
  <title>Angel</title>
  <author id="USA">Jerry</author>
  <description>very good imagination!.</description>
  <location url="file://Derek" />
  </resource>
  </resources>
  </fellow>

The question here is how I can merge the two documents to a new xml
document according to the following given catalogue.dtd

catalogue.dtd

 <!ELEMENT catalogue (items)>
 <!ATTLIST catalogue id ID #REQUIRED>

<!ELEMENT items (item)*>

<!ELEMENT item (type, title, author*, description, location, owner)>
<!ATTLIST item id ID #REQUIRED>

<!ELEMENT type (#PCDATA)>

<!ELEMENT title (#PCDATA)>

 <!ELEMENT author (#PCDATA)>
 <!ATTLIST author id CDATA #REQUIRED>

<!ELEMENT description (#PCDATA)>

 <!ELEMENT location EMPTY>
 <!ATTLIST location url CDATA #REQUIRED>

 <!ELEMENT owner EMPTY>
 <!ATTLIST owner id CDATA #REQUIRED
                   url CDATA #REQUIRED>

I hope there is a quick and simple way to do it !

Thank you very much!