Changing multiple duplicates I hope you guys can help me out here.  I have searched for a very long time and I am not sure if I am wording this correctly.  So thank you for your patients.

I have an object in blender that uses duplicated group instances and it uses a lot of them.  Sometimes I need to change all of these at the same time to a new group instance.  I was hoping there were a way to select all of the instances, change them, and without editing the original version.

The object is a hair brush with multiple bristles.  I have the bristles colored for the product and then I need them rendered next to another brush with different bristles.  When I copy the whole brush with bristles, all the data comes with it.  But if I want a new color and edit the group, it changes on the original brush too.  So now when I make these changes I have to go onto the brush, select every individual bristle, go to the object panel, scroll down to the Duplication section, and select a new instance of the new group for EVERY SINGLE BRISTLE!  And I have been driven to the brink of insanity.  Please help me.  Thank you again!
Select all your dupligroup instances and on the active one change the dupli-group group. Then righ-click the input field and select Copy to Selected:



This will change every object in selection.

You can use this technique on many object properties.