AngularJS Example:

HTML

<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<div ng-app>
  <div ng-controller="PageXCtrl">
      <ul>
          <li ng-repeat="dev in developers">{{dev}}</li>
      </ul>
      <a ng-click="addDeveloper()">Add new one</a>
  </div>
    <div ng-controller="PageYCtrl">
          <ul>
          <li ng-repeat="dev in developers2">{{dev}}</li>
              <a ng-click="addDeveloper2()">Add new one 2</a>
      </ul>

  </div>
</div>

CSS

.done-true {
  text-decoration: line-through;
  color: grey;
}

JavaScript

function PageXCtrl($rootScope, $scope) {
    $rootScope.developers = [1];
    $scope.addDeveloper = function () {
        $rootScope.developers.push(5);
        $scope.developers = $rootScope.developers;
    };
    
    $scope.developers = $rootScope.developers;
}
function PageYCtrl($rootScope, $scope) {
    $scope.developers2 = $rootScope.developers;
     $scope.addDeveloper2 = function () {
        $rootScope.developers.push(7);
        $scope.developers2 = $rootScope.developers;
    };
}