AngularJS: need to attach a selected collection to a model

I'm building a CRUD and I want to some model to be linked to others. So on some update/create template I need to add some other model and save their id when submitting the form. So I did a basic form that is served by my backend. Here is the part where I try to display the linked model:

<div ng-repeat="item in otherItems">
    <select ng-model="item" name="item" >
        <option value="1" ng-selected="item">
        <option value="2" ng-selected="item">
        <option value="3" ng-selected="item">
    </select>
    <a class="remove" ng-click="removeRelated(item)">remove</a>
</div>
<a ng-click="addRelated()"><i class="icon-plus"></i></a>

Note: otherItems could be empty at the beginning (when doing a create or when an item is not linked to any other related model's item). So when one press add/remove it will trigger a controller's function:

$scope.addRelated = function (){
    if (typeof $scope[otherItems]=="undefined")
        $scope[otherItems] = new Array();

    $scope[otherItems].push($scope[otherItems].length);
};

$scope.removeRelated = function (item){
    console.debug(item);
    var idx = $scope[otherItems].indexOf(item);
    if (idx !== -1) {
        $scope[otherItems].splice(idx, 1);
    }
};

My problem is when I save I get the position of item in items (so it's always 0, 1, 2...) I won't have an array of selected ID. I guess there is something wrong with my addRelated maybe. What am I doing wrong?

Here is a screenshot to understand the idea since I may not be very clear: enter image description here

So something like this? http://plnkr.co/edit/6eqWL5

The markup..

<body ng-controller="MainCtrl">
  <div ng-repeat="otherItem in otherItems">
    <select ng-model="otherItem.selectedItem" ng-options="item for item in otherItem.items"></select>
    <a ng-click="removeOtherItem($index)">remove</a>
  </div>
  <a ng-click="addOtherItem()">add</a>
  <hr/>
  Selected:
  <ul>
    <li ng-repeat="otherItem in otherItems">
      otherItem[{{$index}}].selectedItem = {{otherItem.selectedItem}}
    </li>
  </ul>
</body>

The code

app.controller('MainCtrl', function($scope) {
  $scope.otherItems = [
      { 
        selectedItem: null,
        items: [1, 2, 3]
      },
      {
        selectedItem: null,
        items: [4, 5, 6] 
      }
    ];
  $scope.addOtherItem = function(){
    $scope.otherItems.push({ items: [7, 8, 9]});
  };
  $scope.removeOtherItem = function(index) {
    $scope.otherItems.splice(index, 1);
  };
});

Sorry if it's off from what you're asking for... the question was a little vague, so I'm guessing at some of the functionality.