.X File question

I have been recently been doing some DirectX programming and getting into the .x files for the meshes. I been wondering about something that I couldn't find on the net. I have a .x file that is textered somewhat. What I want to happen is that on certain conditions, I want the NON textured parts to be a certain colour, like make the vertices the colour. This would save me some time and space instead of making the model for each colour.

So does anyone know if this can be done? I'm using DX8 and C++6. If you know how to, just tell me the basics of what to do. Thanks.