In an org with person accounts enabled, I am trying to figure out the proper way to perform an upsert. For example, I have ExternalID__PC and externalID__c on the account object. I am wanting to use this field to perform upserts, since it is an externalID. IF I load data to ExternalID__pc, am I correct in assuming that I will only be able to access those values via the contact record? When I attempt an upsert, I only see the externaID__C field as an option to use in data loader. I am able to query the value of the __pc field in dev console, and can see it's metadata within Workbench(not marked as external). I imagine that within SF it will display in the PC field, but anywhere else I try to interact with the value, I must do it via the field on contact. Has anyone else tried this?