Hi pymol-users

I have previously been able to make quite nice visualizations of my volume object, containing the time-averaged density of atoms from a MD-simulation.
For making even more improvement, I'd like to be able to use a script (either python or pml) to control which regions of density gets which color. 

I've found this thread 


that suggests it to be possible, but understanding how to use that for my case is unfortunately (yet) a bit beyond my current pymol-skills.
Ideally I would want to have a solution that allows me to load in my volume-file (in .dx format), assign colors to different regions of density systematically (the Volume-GUI is great, but somewhat tricky to make quick changes with), and display the result on screen.

Is such a thing possible?