You mean creating a Prefab in Unity? In UE4, the equivalent is creating a Blueprint. This might be what you need; however, you will still encounter the issue of applying a material to each component.
in Unity (been a few years since I used it though) there was a feature where you could combine several objects then have an icon representing that collection of items, which you could drag into the scene at anytime, instancing? I cant remember what it was called, but I used it a few times.
Hold on with merging in Blender into one single object or making blueprint with child components as static meshes (parts). There's an option to import ANY model file as a single model in Unreal Engine 4. At the import step, select "Combine Meshes" option to unify all subobjects from the file into one model. This way you…