title: Angular CDK Portal, multiple Portals to one PortalOutlet?
body: <p>So as the title states, is it actually possible using Angular CDK portals/portalOutlets to attach multiple portals to one PortalOutlet, I've been digging through the CDK source code and can't seem to find anything that indicates that it's possible.</p>
  
  <p>Mainly drawing this conclusion on this code within portals.ts.</p>
  
  <pre><code>attach(portal: Portal&lt;any&gt;): any {
    if(!portal) {
      throwNullPortalError();
    }
  
      if(this.hasAttached()) {
    throwPortalAlreadyAttachedError();
  }
  
  if (this._isDisposed) {
    throwPortalOutletAlreadyDisposedError();
  }
  
  if (portal instanceof ComponentPortal) {
    this._attachedPortal = portal;
    return this.attachComponentPortal(portal);
  } else if (portal instanceof TemplatePortal) {
    this._attachedPortal = portal;
    return this.attachTemplatePortal(portal);
  }
  </code></pre>
  
  <p>I can obviously create multiple portalOutlets or lets say overlays in this scenario and attach a component portal to each overlay individually using the componentFactoryResolver, but again not really the scenario I'm after. </p>