2 layers render in three

import * as THREE from 'three';

			import { TrackballControls } from 'three/addons/controls/TrackballControls.js';
			import { CSS3DRenderer, CSS3DObject } from 'three/addons/renderers/CSS3DRenderer.js';

			let camera, scene, renderer;
			let controls;
			

			function Element( id, x, y, z, ry ) {

				const div = document.createElement( 'div' );
				div.style.width = '480px';
				div.style.height = '360px';
				div.style.backgroundColor = '#000';

				const iframe = document.createElement( 'iframe' );
				iframe.style.width = '480px';
				iframe.style.height = '360px';
				iframe.style.border = '0px';
				iframe.src = [ 'https://www.youtube.com/embed/', id, '?rel=0' ].join( '' );
				div.appendChild( iframe );

				const object = new CSS3DObject( div );
				object.position.set( x, y, z );
				object.rotation.y = ry;

				return object;

			}

			init();
			animate();

			function init() {

				const container = document.getElementById( 'container' );

				camera = new THREE.PerspectiveCamera( 50, window.innerWidth / window.innerHeight, 1, 5000 );
				camera.position.set( 500, 350, 750 );

				scene = new THREE.Scene();

				renderer = new CSS3DRenderer();
				renderer.setSize( window.innerWidth, window.innerHeight );
				container.appendChild( renderer.domElement );

        let wallGeo1 = new THREE.BoxGeometry(0.1, 100, 100);

        let wallMat = new THREE.MeshPhongMaterial({ color: 0x000000 });
    
        let wall1 = new THREE.Mesh(wallGeo1, wallMat);

        wall1.position.set(0,0,0);
        
        scene.add(wall1);
    

				const group = new THREE.Group();
				group.add( new Element( 'SJOz3qjfQXU', 0, 0, 240, 0 ) );
				// group.add( new Element( 'Y2-xZ-1HE-Q', 240, 0, 0, Math.PI / 2 ) );
				// group.add( new Element( 'IrydklNpcFI', 0, 0, - 240, Math.PI ) );
				// group.add( new Element( '9ubytEsCaS0', - 240, 0, 0, - Math.PI / 2 ) );
				scene.add( group );

				controls = new TrackballControls( camera, renderer.domElement );
				controls.rotateSpeed = 4;

				window.addEventListener( 'resize', onWindowResize );

				// Block iframe events when dragging camera

				const blocker = document.getElementById( 'blocker' );
				blocker.style.display = 'none';

				controls.addEventListener( 'start', function () {

					blocker.style.display = '';

				} );
				controls.addEventListener( 'end', function () {

					blocker.style.display = 'none';

				} );

			}

			function onWindowResize() {

				camera.aspect = window.innerWidth / window.innerHeight;
				camera.updateProjectionMatrix();
				renderer.setSize( window.innerWidth, window.innerHeight );

			}

			function animate() {

				requestAnimationFrame( animate );
				controls.update();
				renderer.render( scene, camera );

			}