No - the built in Active Directory import uses a query that obtains user details for the entire domain.
Best practice to make changes would then involve turning off the default AD import and creating a custom import?
Do you know if the SCCM import also imports users?
@rwiltshire The SCCM import does import Users. If you turn off the default AD import you would need to populate the sites and subnets via an adapter as well. The AD adapter pulls users, computers, and Sites & Subnets. The sites and subnets get assigned to the beacons that manage those areas of your network.
This article notes the elements imported by the default AD import.