New-DynamicDistributionGroup -Name AllUsers -OrganizationalUnit "OU=PS,DC=PS,DC=local" -RecipientContainer "OU=PS,DC=PS,DC=local" -RecipientFilter "(RecipientTypeDetails -eq 'UserMailbox') -or (RecipientTypeDetails -eq 'SharedMailbox')"

$group = (Get-DynamicDistributionGroup -Identity AllUsers)

Get-Recipient -RecipientPreviewFilter ($group.RecipientFilter)

Get-Recipient -RecipientPreviewFilter ($group.RecipientFilter) | measure

Get-MailboxStatistics Alexander.Reed@ps.local

Send-MailMessage -From Alexander.Reed@ps.local -To Oscar.Wood@ps.local -Subject "Test Email" -SmtpServer "192.168.1.113" -Body "Test Email Body"