This depends on your purpose. If you know that appropriate OU in Active Directory should always have installed SMA (after image restore, etc), then using GPO from AD, your computers will always be checked, whether there is SMA installed or not and then execute installation of SMA on appropriate PC from appropriate OU.
In SMP Console you can import OUs via Active Directory Import or create own Organizationa Views/Orgranization Groups, where will be located appropriate computers.