Can someone help me write the appropriate xsl transformation to output a xml 
document where duplicates have been filtered out. In my input document, two 
"rows" are duplicates if they use the same unique identifier field (as 
determined by an attribute called 'uniqueidfield') and the value in this 
field is the same. In the following example, there are two duplicate accounts 
with the accountid 'ABC' but there is also a contact with the same id. The 
output document should contain one of the two 'ABC' accounts (I don't really 
care which one) and it should also containt the 'ABC' contact.

Input:
<resultset>
  <result uniqueidfield="accountid"><accountid>abc</accountid><name>abc 
corp.</name></result>
  <result uniqueidfield="accountid"><accountid>def</accountid><name>def 
ltd.</name></result>
  <result uniqueidfield="accountid"><accountid>abc</accountid><name>abc 
corp. 2</name></result>
  <result uniqueidfield="contactid"><countactid>abc</contactid><name>John 
Smith</name></result>
<resultset>

Desired output:
<resultset>
  <result uniqueidfield="accountid"><accountid>abc</accountid><name>abc 
corp.</name></result>
  <result uniqueidfield="accountid"><accountid>def</accountid><name>def 
ltd.</name></result>
  <result uniqueidfield="contactid"><countactid>abc</contactid><name>John 
Smith</name></result>
<resultset>