Adding unique options to a list box.

First I want to say thanks to all those here who gave me suggestions to
my early issues.  They worked like a change.  I am making progress
learning this stuff!!!

However, a new issue has cropped up and I need a bit of help again.

I have an XML file that lists out tasks and as children, each task has
several elements named "attributes".  Each of these attribute tags has
an attribute identifier such as name, resource, start time etc...

I want to populate a list box with the resource elements so that
(eventually) the user can sort the tasks by resources.  The problem is
that several tasks have the same resource and some have none assigned at
all.  I now have the XSL search through the XML tree and populate the
list box.  I of course get every instance of the resource elements put
into the list box...including blanks where there is no resource assigned
in the xml.  My question is how do I test so that I am only populating
the resource into the list box once and also skip over populating the
empty elements.


Hope that makes sense.

Thanks

Marc

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