Only Peer Number (CallerID) is used by the OBi to route calls. Peer Name (CName) is simply passed through to the Phone Port for use by your telephone display if you have one.
If your international calls have anything unique about their CallerID, then you can use this to route the calls. For example if their CallerIDs all contain 12 digits or more, then you could use an InboundCallRoute such as:
{(xxxxxxxxxxxxx.|01519999999):aa},{ph}