Return only unique values from XML CWP...???

[angelleye]

I'm using the following call to return email addresses from our database based on buyers of a certain product in our database:

https://server.com/fmi/xml/fmresultset.xml?-db=Invoices&-lay=waGetEmails&-sortfield.1=Leads_Clients::Email_Address&Invoice_Items::Description="&ProductDescription&"&-find

This returns results just fine, however, if the same person bought the same type of item more than once their email is getting returned multiple times.

How can I filter this so that it only returns unique values? Basically, I need the equivalent of a SQL SELECT DISTINCT statement.

Any information would be greatly appreciated. thanks!