Reimport FBX With New Objects

I need to reimport an FBX file that has new objects inside the hierarchy. The new objects just don’t get imported. All the other objects that are already in unity get updated when I reimport the fbx but no new objects are added.
Is this not possible? Do I need to delete the GameObject inside Unity and add the Mesh again? That would be pretty annoying because there are many scripts and things associated to the subobjects of the FBX.

In order to update prefabs inside of your scene, you must re-place them with the new import.