Just quick post. You have dynamic distribution group, you need to scope it for special container and you need to preview recipients for that DDL just inside the container. Solution is easy. Use Where condition and with definition of recipient container in for of distinguished name:
$x = Get-DynamicDistributionGroup mailNY
GetRrecipient -RecipientPreviewFilter $x.recipientfilter |Where {$_.Distinguishedname -like "*OU=subou,OU=ou,DC=domain,DC=suffix"} |select *city*,distinguishedname
Easy? Yes, but I always forgot how I did it, so that is why I posted it.