Linked group object color

In a scene with library linked objects I wonder if there is a way to change the object color in game engine.
For a local object I have to add an IPO in the ObjCol channel.
How can I do with group instances? Make all object local? How if they are instanced with an empty?

I’ve always done it with curves, the way you explained. Have you tried using a script to access the color?
KX_GameObject has a color property, I don’t know if that’ll work.

Ok, i’ve found an alternative way instead of keep instanced groups, i make them all “Duplicate real”.

That means instead of empties with linked dupligroup, i have in the scene objects with linked meshes.

To make this is possible selecting all instanced groups and press SHIFT+CTRL+A in blender 2.5.