Bone structure: problems and questions

Hi,
I'm new to the community of Grasshopper . 

I'm use Rhinoceros for years, but now I'm starting to use too Grasshopper.
I am writing to have suggestion regarding a Project what I should to male.



I am a student of Biology and I deal with 3D modeling in the biomedical field.



I have to make a 3D model of trabecular bone that have a structure like this:

http://www.gla.ac.uk/t4/~fbls/files/fab/images/generic/boporos4.jpg  



To do this I am following " Skeletal Mesh" tutorial posted here:

http://www.grasshopper3d.com/forum/topics/skeletal-mesh?page=5  



My problem is this: I need to increase and decrease the density of the structure only in some parts of the solid model with simply numerical number. So I'm not interested in a trabecular structure uniform but in some parts of the solid , this structure must bemore or less uniform.  

Is it possible with Grasshopper define different densities from numerical number for different parts of the same solid?  

Thanks for the support.

Luca