Script Repository

$sourceUserDNAttribute = "assistant" # TODO: modify me

# Get source mailbox DN
try
{
    $sourceUserDN = $Context.TargetObject.Get($sourceUserDNAttribute)
}
catch
{
    $Context.LogMessage("Source user not specified", "Warning")
    return
}

# Get Microsoft 365 object IDs
$sourceUser = $Context.BindToObjectByDN($sourceUserDN)
try
{
    $sourceUserObjectId = [Guid]$sourceUser.Get("adm-O365ObjectId")
}
catch
{
    $Context.LogMessage("The source user doesn't have a Microsoft 365 account", "Warning")
    return
}

try
{
    $targetUserObjectId = [Guid]$Context.TargetObject.Get("adm-O365ObjectId")
}
catch
{
    $Context.LogMessage("This user doesn't have a Microsoft 365 account", "Warning")
    return
}

# Connect to Exchange Online
$Context.CloudServices.ConnectExchangeOnline()
    
# Get all distribution groups in Microsoft 365
$groups = Get-DistributionGroup -ResultSize unlimited
foreach ($group in $groups)
{
    if ($group.IsDirSynced)
    {
        continue
    }
    
    # Skip group if source user is not member
    if (!(Get-DistributionGroupMember $group.Identity | Where{$_.ExternalDirectoryObjectId -eq $sourceUserObjectId.ToString()}))
    {
        continue
    }
    
    try
    {
        # Add target user to group
        Add-DistributionGroupMember $group.Identity -Member $targetUserObjectId.ToString() -Confirm:$False -ErrorAction Stop
    }
    catch
    {
        $Context.LogMessage("Cannot add the target user to group $($group.Identity). Error message: " + $_.Exception.Message, "Warning")
    }
}