AngularJS +指令：多个被包含的元素

我正在尝试添加一个body指令，该指令将具有一个左面板和一个右面板。但是在这些面板之间，我将有一些body指令专有的内容。我目前正在使用transclude = true选项加​​载内容。但是，我正在寻找一种使用两个ng-transclude的方法。我研究了很多解决方法，但是找不到理想的解决方案。我必须在body指令的编译步骤中手动添加已包含的对象。以下是我解决该问题的方法：

身体指令

var myApp = angular.module('myApp', []);

myApp.directive('body', function () {
    return {
        restrict: 'A',
        transclude: true,
        scope: {
            title: '@'
        },
        templateUrl: 'body.html',
        compile: function compile(element, attrs, transclude) {
            return function (scope) {
                transclude(scope.$parent, function (clone) {
                    for (var i = 0; i < clone.length; i++){ 
                       var el = $(clone[i]);
                       if(el.attr('panel-left') !== undefined) {
                            element.find('#firstPanel').html(el);
                       } else if(el.attr('panel-right') !== undefined) {
                            element.find('#secondPanel').html(el);
                       }
                    }
                });
            }
        }
    };
});

myApp.directive('panelLeft', function () {
    return {
        require: "^body",
        restrict: 'A',
        transclude: true,
        replace: true,
        template: '<div ng-transclude></div>'
    };
});

myApp.directive('panelRight', function () {
    return {
        require: "^body",
        restrict: 'A',
        transclude: true,
        replace: true,
        template: '<div ng-transclude></div>'
    };
});

模板

<script type="text/ng-template" id="body.html">
    <h1> {{title}} </h1>
    <hr/>

    <div id="firstPanel" class="inner-panel"></div>
    <div id="innerMiddleContent" class="inner-panel">middle private content here</div>
    <div id="secondPanel" class="inner-panel"></div>
</script>

<div body title="Sample Body Directive">
    <div panel-left>
        Public content that goes on the left
    </div>   

    <div panel-right>
        Public content that goes on the right
    </div>    
</div>

这是此示例的JSFiddle。我正在寻找这样的东西：

必备模板

 <script type="text/ng-template" id="body.html">
     <h1> {{title}} </h1>
     <hr/>

     <div id="firstPanel" class="inner-panel" ng-transclude="panel-left"></div>
     <div id="innerMiddleContent" class="inner-panel">middle private content here</div>
     <div id="secondPanel" class="inner-panel" ng-transclude="panel-right"></div>
 </script>

问题：我做错什么了吗？是否有解决此问题的推荐方法？