Using XML in PowerShell together with SCCM task sequence var

$tsenv = New-Object -COMObject Microsoft.SMS.TSEnvironment

# inline xml:
$xml = [xml]@"
<workplaces>
   <computer id="F">
      <ou></ou>
      <title>Flexible</title>
   </computer>
   <computer id="B">
      <ou></ou>
      <title>Business</title>
   </computer>
</workplaces>
"@

# xml in file:
$xml = [xml](gc "testfile.xml")

# read computer type from the task sequence
$workplace= $tsenv.Value("Workplace")

# query the xml
$title = ($xml.workplaces.computer | where { $_.id -ieq "B" }).title
$ou = ($xml.workplaces.computer | where { $_.id -ieq "$workplace" }).ou

# write SCCM task sequence variabele
$tsenv.Value("OU") = $ou