For those synchronizing contacts Gmail<->Highrise or Exchange<->Highrise:
1. Any Highrise contact created/updated by Yoxel in Gmail/Exchange will be tagged with the special external name "Highrise" so you'll see what came from or exists in Highrise.
2. You may not want to enable the sync for all your Gmail/Exchange contacts so choose the "sync only contacts tagged with" mode and specify one "sync enabling tag". The "Highrise" name is a good choice because that group/category will be created in your Gmail/Exchange account anyway.