[NTG-context] Font sizes in item group

I am trying to find out it there is a way to set the font size for each level of an item group so that as you go down the item group, the font decreases a small amount. I assume there must be a way, but I haven't found anything looking around the manuals. Here is my current item group. \defineitemgroup[bullet][levels=3] \setupitemgroup[bullet][1][1] \setupitemgroup[bullet][2][2] \setupitemgroup[bullet][3][3] Thanks, Mike