Using XPath to select multipel unique values

Hello, I am having a little bit of trouble with xpath.

I have an xml file in the following format:

<?xml version="1.0" encoding="UTF-8"?>
<dataroot xmlns:od="urn:schemas-microsoft-com:officedata" xmlns:xsi=""  xsi:noNamespaceSchemaLocation="Sales%20Reps.xsd" generated="2012-01-30T17:08:58">
		<CustomerName>Abel &amp; Young</CustomerName>
		<CustomerName>Department of CIS</CustomerName>
		<CustomerName>Advantage Sales</CustomerName>

I need to retrieve a list unique list of sales reps and thier id’s. So far I have been able to get as far as getting a list of just the reps ID’s with this expression:


I am having a hard time figuring out how to select the ID, last name and first name however. This is the expression that I am trying to use to find unique combinations but it’s not working and I’m not sure how to get the 3 values out.

dataroot/Sales_x0020_Reps[not(concat(SalesRepID, LastName, FirstName)=preceding-sibling::Sales_x0020_Reps/concat(SalesRepID, LastName, FirstName))]

Any ideas?