ldap / filters

System

I currently have serveral LDAP links set up that synchronize to the top levels which are location. (ie.. NY, LONDON, MADRID)

Within the Active Directory, I also have lower level OU's under each called Computer Names. Unfortunately these are being brought in as enabled objects via the synch process.

What is the best way to exclude them?

Can anyone explain the Group Filter and what that actually does?

Thanks