Threejs: glb file reflect the environment but not itself

In threejs, I successfully import and display a glb file of a house (the house has two floors and various objects on each floor, among which chairs, some tables, a kitchen etc, such as a real house). My problem is that I am able to make the house and its objects reflect the environmental light but I am not able to make the objects of the house reflect themselves. My ultimate goal would be to implement some real time ray-tracing, but at this point I would be happy to only generate some real time reflections which in addition to the environmental light also reflect the other objects of the house. Same with shadows.

I have not found anything online about it this type of reflections. Does anyone know a good place where to start? Or if you have faced a similar challange, how did you solve it?