grouping of query data in xml

Hi friends,

I am working with some xml exporting functionality of our application. I am
testing query_to_xml function supported in PostgreSQL 9.1. XML output
should be
<accgroup>
<accgroupid>1</accgroupid>
<accgroupname>COMPANY ACCOUNT</accgroupname>
<docs>
<refaccdocid>638168</refaccdocid>
<debit>10000.0000</debit>
<credit>0.0000</credit>
</docs>
<docs>
<refaccdocid>638168</refaccdocid>
<debit>0.0000</debit>
<credit>10000.0000</credit>
</docs>
</accgroup>

but the output is as follows:
<row>
<accgroup>acc group</accgroup>
<accgroupid>1</accgroupid>
<accgroupname>COMPANY ACCOUNT</accgroupname>
<docs>docs</docs>
<refaccdocid>638168</refaccdocid>
<debit>10000.0000</debit>
<credit>0.0000</credit>
</row>

<row>
<accgroup>acc group</accgroup>
<accgroupid>1</accgroupid>
<accgroupname>COMPANY ACCOUNT</accgroupname>
<docs>docs</docs>
<refaccdocid>638168</refaccdocid>
<debit>0.0000</debit>
<credit>10000.0000</credit>
</row>

How can grouping on specific columns can be done in result xml through
using query_to_xml?
I am expecting help from postgresql community as always.

Thanks

CPKulkarni