I am not sure if this is what you wanted. But i use ng-change to setup the new filter value.
Controller:
function AccordionDemoCtrl($scope) {
$scope.oneAtATime = true;
//default: all countrys
$scope.country = '';
//example data
$scope.listcity = [{
name: 'Madrid',
country: '3'
}, {
name: 'Paris',
country: '2'
}, {
name: 'Lyon',
country: '2'
}, {
name: 'Zurich',
country: '1'
}];
//set a new selection
$scope.setCountry = function(cid) {
$scope.country = cid;
}
}
Markup:
<select ng-model="country" ng-change="setCountry(country)" class="input-medium inputFilter form-control">
See it working here
Btw: The example directive is the shortest I have ever seen. Ahh, I whish it was that easy:-)