javascript – Load additional objects on demand using Autodesk Viewer v7 (Forge Viewer)

I have integrated Viewer into my application. The Viewer loads SVF 3D models from the Autodesk Platform Services. However, for large models it can take significantly more time to load entire model. I want to load objects on demand when user chooses needed object. For example, user can choose to load only roofs and walls initially. After that, user can choose additional objects to load on demand.

First of all, using the Autodesk Platform Services API, I received the list of model views using List Model Views and fetched the object tree using Fetch Object Tree apis. After that I used viewer.loadModel(urn, { ids: [] }) to load model using ids received from object tree. However, when I called this method one more time, it loaded the needed objects into the new model on the scene, which can be viewed in the Model Browser tool of GuiViewer3D.

Is it possible to load these new ids additionally into the existing loaded model?