Here is an example of a stud rails family that has 4 nested identical families. My interest is to modify the "Angle" instance parameter on the selected stud rail (tabbing to select the child family) so I could modify the slope of this instance. The "Angle" is an instance parameter and is not tied up the chain to the parent.
At present if I have to do this then I have to create 4 instance parameters and give them values such that the one selected is controlled from the parent family as input.
I believe with this ability we would have more control over how we use Nested families and build some flexibility without using Model Groups.
