<tr ng-repeat="add in addRights">
<td>
<select ng-model="groupId[$index]">
<option value="">(по умолчанию)</option>
<option ng-repeat="group in unUsedGroups" value="{{group.ID}}">{{group.NAME}} [{{group.ID}}]</option>
</select>
</td>
</tr>
$scope.$watch('groupId[$index]', function(newValue, oldValue){
});