I have created a light bulb and I want all the objects of the light bulb "behave as one entity". So I thought I should create an empty and make that empty the parent of all child objects (together the light bulb). But now it is still possible to select and move an individual child object. And I don't want that. If I select the glass and move that I want the whole light bulb to move.
I want to build a library of 3D models and I want to be able to append a 3D model (for instance a light bulb) and move that model in my scene. But I do't want to join all meshes, I want the individual child objects to stay separate objects.