AngularJS Example:

HTML

<link rel="stylesheet" href="http://twitter.github.com/bootstrap/assets/css/bootstrap.css">
<div ng-app>
  <div ng-controller="GroupViewerController">
          <table class="table table-striped" >
		        <tr ng-repeat="a in arr" ng-controller="OneGroupViewerController">
              <td >{{a}} <button ng-click="change(a)">change</button></td>
		        </tr>
	        </table>
  <div ng-controller="oneGroupItemsController">
    <input type="text" ng-model="$parent.updateVar.selectedObject">
  </div>
  </div>

  </div>

JavaScript

function GroupViewerController($scope) {
  $scope.updateVar = {};
  $scope.updateVar.selectedObject = "test";
  $scope.arr = ["a","b"]
}

function OneGroupViewerController($scope) {
  $scope.change = function (a){
       $scope.$parent.updateVar.selectedObject = a;
  }
}

function oneGroupItemsController($scope) {
 
}