Overview
You want to filter which OUs are synchronized from Active Directory.
Solution
This is not a current feature of LanGuard.
As an alternative, depending on your environment, you may want to opt for disabling AD synchronization and adding any new devices to the LanGuard computer tree either manually or through a text file import.
If you want to see OU filtering capabilities added in future versions, you can submit a feature request directly to the product management group.