This manipulation got no shortcut at the time. This group type is quite different from
3D Group
If you got too many mesh in your imported files and you want to put the same material (
3D Renderer) over all of them, you can Group their generators as followed :
First select all the mesh you want to group and do a right click:
Then choose a
3D Renderer among the list.
And there you go, no a single material is applied on the overall geometries. Note that in this status,
3D Modifier can also be applied on many different mesh altogether: