[Kazun]

Код:

$result = Import-Csv users.csv -Delimiter ";" | 
	Group {"{0} {1} {2}" -f $_.Имя,$_.Отчество[0],$_.Фамилия} | Where {$_.Count -eq 1} | Foreach {
		$name = $_.Name
		$sam = (Get-ADUser -Filter "DisplayName -eq '$name'").SamAccountName
		if(Get-ADUser -Filter "DisplayName -eq '$name'") {
			$_.Group | Add-Member -NotePropertyName SamAccountName -NotePropertyValue $sam -PassThru
		}
		else {
			$_.Group | Add-Member -NotePropertyName SamAccountName -NotePropertyValue "" -PassThru
		}
	}