Get all machines in a reservation with PowervRA
$ReservationName = "Reservation1"
$CatalogResources = Get-vRAConsumerResource -WithExtendedData | ? {($_.ResourceType -eq "Infrastructure.Virtual") -and ($_.Data.MachineReservationName -eq $ReservationName)}
$CatalogResources | Select ResourceId, Name, @{Name="Reservation"; Expression={$_.Data.MachineReservationName}}