Conditional processing by matching elements

I'm trying to match SERVICED from the SecondStruct structure with that of
the FirstStruct structure and print out messageOne if the SERVSTAT="Y". If
there is no matching SERVICEID in FirstStruct, print out messageTwo. For
example, my output could look like this:

Service1	On
Service2	Off
Service3	Off
Service4	On
Service5	Off
Service6	Off
Service7	Off

What is a good way to do this?? Thanks for your help.

<Structure StructId="FirstStruct" rowCount="2">
<Row SERVICEID="Service1" NAME="Service One " SERVSTAT="Y" />
<Row SERVICEID="Service4" NAME="Service Four" SERVSTAT="Y" />
</Structure>
<Structure StructId="SecondStruct" rowCount="7">
<Row SERVICEID="Service1" NAME="Service One" />
<Row SERVICEID="Service2" NAME="Service Two" />
<Row SERVICEID="Service3" NAME="Service Three" />
<Row SERVICEID="Service4" NAME="Service Four" />
<Row SERVICEID="Service5" NAME="Service Five"  />
<Row SERVICEID="Service6" NAME="Service Six" />
<Row SERVICEID="Service7" NAME="Service Seven" />
</Structure>

 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list