Auto-Sorting Computers in WSUS

When I installed my first WSUS server, I liked the idea of auto-assigning computers into different WSUS groups according to domains using the group policy’s settings.
However, it’s a bummer to find out that you can only assign every computer to one group using GP (and not being able to manually assign), or avoid GP groups at all and assign computers manually.
Eventually I ended up creating this PowerShell script that checks for unassigned computers nightly, and assigns them to the right groups.

<#
.SYNOPSIS
Sorts unassigned WSUS clients into domain-matching groups
 
.Description
This scripts loops over all unassigned computer records in WSUS, and assigns each one to the group with a name matching it's single-lable domain name, if such a group exists.
 
.EXAMPLE
Sort-WSUSComputers.ps1 'WSUS1'
 
.LINK
My Blog: http://blog.backslasher.net
#>
param(
[parameter(Mandatory=$true)]
[string]$wsusServer
)
 
$dnsDomain = $env:USERDNSDOMAIN;
$Domain = $env:USERDOMAIN;
$topDomain = $dnsDomain -replace ('^'+[regex]::escape($Domain)),''
$ErrorActionPreference = 'stop';
[reflection.assembly]::LoadWithPartialName("Microsoft.UpdateServices.Administration")
$wsus = [Microsoft.UpdateServices.Administration.AdminProxy]::GetUpdateServer($wsusServer,$false);
 
# locate the "unassigned" group
$Unassigned = ($wsus.GetComputerTargetGroups() | ?{$_.Name -eq 'Unassigned Computers'}).GetComputerTargets();
$Unassigned | %{
    $Domain = ($_.FullDomainName -replace '(^[^\.]+\.)|('+[regex]::escape($topDomain)+'$)','');
     
    # Find the matching group
    $Group = ($wsus.GetComputerTargetGroups() | ?{$_.Name -eq $Domain});
     
    # Add the computer
    if($Group) {$Group.AddComputerTarget($_)}
}