Taper Command

Hi all,

I've got a fairly limited, but usable knowledge of Grasshopper and how to usually search through tutorials and forums to find my answers. However in this case I can't find any way to perform a Taper. 

The Rhino command does exactly what I need it to do. Does anyone know how to achieve this same result from GH alone. 

Note: It would be beneficial to be able to select multiple objects and taper them at the same time, using the same reference points (as with the Rhino tool).