Using depends with ( "selector" ).rules( 'add', { .... } )

Question

In my form the zipcode input comes before the State input. Therefore, I want to validate my zipcode only after my State input has been filled out. I have gotten the remote part to work. I have not been able to figure out how to use the "depends" of the jQuery Validation plugin. Due to the CRM that I am using, I need to use the .rules('add', {...}) way of setting up validation. Here is the code I am using:

      CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_postal-code-5, " +
        ".com_civicrm form[class^='CRM_'] #postal_code-1"
        ).rules('add', {
            remote: function () { 
                var r = {
                    url:    "http://localhost:81/example.org/media/plg_civcrm_frmvalidation/php/val-zip.php",
                    data:   {
                        address2: function() {
                            return CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_street_address-5, " +
                                ".com_civicrm form[class^='CRM_'] #street_address-1"
                            ).val();
                        }, 
                        city: function() {
                            return CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_city-5, " +
                                ".com_civicrm form[class^='CRM_'] #city-1"
                            ).val(); 
                        },
                        state: function() {
                            return CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_postal-code-5, " +
                                ".com_civicrm form[class^='CRM_'] #state_province-1"
                            ).val();
                        },
                        zipcode: function() {
                            return CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_postal-code-5, " +
                                ".com_civicrm form[class^='CRM_'] #postal_code-1"
                            ).val();
                        },
                    },
                    type: "post",

                    depends: function(element) {
                        return CRM.$(".option-com-civicrm form[class^='CRM_'] #billing_postal-code-5, " +
                                ".com_civicrm form[class^='CRM_'] #state_province-1"
                        ).val() !== '';
                    }
                };

                return r;
            }

        });