Multiscreen synchronization

Hi everyone, I am a newbie at Cesiumjs. In a project I have multiple screens 3D and 2D. I have their synchronization for zoom-in zoom-out from sandcastle examples. However, I want to make them more synchronized so that I will need to add an entity to 3D viewer only and it will also appear on 2D screen too. This way I’m aiming to improve the performance of my program and release it from extra entity addition for the second screen. I heard that Cesium has a feature for it but I couldn’t find it. Could you help out on this please? Greetings.