How to create an array or group of Directives in Angular 2
<p>I currently have a module with a Component and a Directive which supports the Component in my Angular 2 app. For the user to use this Component they have to import both the Component and the Directive. Is there a way that I can group them into something like <code>ROUTER_DIRECTIVES</code></p>

<p>For eg:</p>

<pre><code>import {Component, HostListener, Directive} from "angular2/core";

@Component({
    selector: "my-dropdown",
    templateUrl: "./dropdown.html",
    styleUrls: ["./dropdown.css"]
})
export class Dropdown {
    //code
}

@Directive({
    selector: ".my-dropdown-toggle"
})
export class DropdownToggle{

    //code
}
</code></pre>

<p>To use this the user has to import like this:</p>

<pre><code>@Component({
    moduleId: module.id,
    directives: [Dropdown,DropdownToggle,ROUTER_DIRECTIVES],
    templateUrl: "./dropdown-sample.html"
})
export class DropdownAngularDemo {
}
</code></pre>

<p>I want to know if I can group <code>Dropdown</code> and <code>DropdownToggle</code> into an array like <code>ROUTER_DIRECTIVES</code></p>