Powershell – Data put into an array goes away after exiting ForEach-Object loops

Originally I ran into this while trying to combine AD groups and user members into an array of objects to process and export into a csv file but the following script fragment does the same thing. I am using Powershell ISE  Versiion 3

Clear-Host
$Groups = 'Group1', 'Group2'
$Users = 'User1', 'User2'
[array]$GroupUsers=$null

$OneGroupUsers = New-Object PSCustomObject
Add-Member -InputObject $OneGroupUsers -MemberType NoteProperty -Name OneGroup -Value ""
Add-Member -InputObject $OneGroupUsers -MemberType NoteProperty -Name OneUser -Value ""

$Groups | ForEach-Object {
  $OneGroup = $_  #.SamAccountName
  ######  Get-ADGroupMember -Identity $OneGroup -Recursive
  $Users | ForEach-Object {
    $OneUser = $_ #.SamAccountName
    $OneGroupUsers.OneGroup =$OneGroup
    $OneGroupUsers.OneUser = $OneUser

    $GroupUsers += $OneGroupUsers
    Write-Host "Inside the loops I seem to have the right data $($GroupUsers[-1]) "
  } # End ForEach-Object
}# End ForEach-Object

Write-Host " what happened to the data once I exit the loops."
$GroupUsers.count

$GroupUsers

The results

Inside the loops I seem to have the right data @{OneGroup=Group1; OneUser=User1}
Inside the loops I seem to have the right data @{OneGroup=Group1; OneUser=User2}
Inside the loops I seem to have the right data @{OneGroup=Group2; OneUser=User1}
Inside the loops I seem to have the right data @{OneGroup=Group2; OneUser=User2}
 what happened to the data once I exit the loops.
4

OneGroup                                                    OneUser
——–                                                    ——-
Group2                                                      User2
Group2                                                      User2
Group2                                                      User2
Group2                                                      User2

What am I doing wrong??