how to split xml using xpath in perl?

i have a input xml which i have to split based on doc and delt wise and save it in this format delt_0001.xml

This is my code

    #!/usr/bin/perl
    use XML::XPath;

    my $file = 'file.xml';

    my $xp = XML::XPath->new(filename=>$file);

     foreach my $entry ( $xp->findnodes('/xml/service/main/doc') ) {
       my $filename = $entry->findvalue('./delt/@id');
      foreach my $entry1( $entry->findnodes('//delt')){

     my $filename = $entry1->findvalue('/delt/@id');
         my $content  = $entry1->toString;
    open(wr,">delt_$filename.xml");
    print wr "$content\n";
    close wr;

    }

When i run the program all delt portion prints in one xml.

input xml delt.xml

  <xml>
<service>
<title>split xml</title>
<main>
<doc id="001">
<title>doc1</title>
<delt id="0001">
<title>delt1</title>
<text>num1</text>``
<text>num1</text>
</delt>
<delt id="0002-A">
<title>delt1</title>
<text>num1</text>
<text>num1</text>
</delt>
</doc>
<doc id="002">
<title>doc2</title>
<delt id="0003">
<title>delt1</title>
<text>num1</text>
<text>num1</text>
</delt>
<delt id="0004">
<title>delt1</title>
<text>num1</text>
<text>num1</text>
</delt>
</doc>
</main>
</service>
</xml>

output am geting

         <delt id="0001">
        <title>delt1</title>
        <text>num1</text>``
        <text>num1</text>
        </delt>
        <delt id="0002-A">
        <title>delt1</title>
        <text>num1</text>
        <text>num1</text>
        </delt>
       <delt id="0003">
        <title>delt1</title>
        <text>num1</text>
        <text>num1</text>
        </delt>
        <delt id="0004">
        <title>delt1</title>
        <text>num1</text>
        <text>num1</text>
        </delt>

output needed

split no 1 delt_0001.xml

<xml>
<service>
<title>split xml</title>
<main>
<doc id=001>
<title>doc1</title>
<delt id=0001>
<title>delt1</title>
<text>num1</text>``
<text>num1</text>
</delt>
</doc>
</main>
</service>
</xml>

split no 2 delt_0002-A.xml

<xml>
<service>
<title>split xml</title>
<main>
<doc id=001>
<title>doc1</title>
<delt id=0002=A>
<title>delt1</title>
<text>num1</text>
<text>num1</text>
</delt>
</doc>
</main>
</service>
</xml>

split no 3 delt_0003.xml

<xml>
<service>
<title>split xml</title>
<main>
<doc id=002>
<title>doc2</title>
<delt id=0003>
<title>delt1</title>
<text>num1</text>
<text>num1</text>
</delt>
</doc>
</main>
</service>
</xml>

split no 4 delt_0004.xml

<xml>
<service>
<title>split xml</title>
<main>
<doc id=002>
<title>doc2</title>    
<delt id=0004>
<title>delt1</title>
<text>num1</text>
<text>num1</text>
<delt>
</doc>
</main>
</service>
</xml>

Thanks in advance