How do you organise your objects in the outliner?

I’d like to know what is the best way to sort elements in Blender?

For example, I have this car that is composed by different elements. I create empties to organize my outliner.
CAR -> mesh -> elements of my car.
Those empties are not there to be move, this is not the rigging but just a way to sort elements. I like that but the problem is that when the car is moving, the parenting is displayed in the 3D view (dotted lines) even if the empty is not displayed (view to off in the outliner). Is there a way to disable that? or is there a better way to sort elements?

An other way is simply to use groups. In the outliner there is a group setting which only displays groups.

you can disable the relationship lines ( n panel-display-relationship lines)