Two or more ion-slides instance issue


I am using two ion-slides and I am trying to manage them in the controller by using:

$scope.$on("$ionicSlides.sliderInitialized", function(event, data){
  // data.slider is the instance of Swiper
  $scope.slider = data.slider;


but it takes only effect on the second ion-slider. Is there a way to instance each slider separately?