'Override superclass method to resolve against the pr_person
resource instead of the master resource (=hrm_human_resource)
@param resource: the resource
@return: a tuple (self, None, Field instance)'

def resolve(self, resource):

    selector = self.selector
    person_resource = current.s3db.resource('pr_person', components=[selector])
    return super(S3SQLHRPersonLink, self).resolve(person_resource)
