You can do something like what your asking with multiple scenes. Bear in mind, you will have a lot of extra work/tweaking/headaches when you have to adjust two scenes, but if it's necessary it's worth the trouble. Just link objects that shouldn't change between scenes (i.e. camera/lights)

Scene Setup

1. Create a new scene
2. Move your cycles object (the windows) to "Scene.001" (CtrlL > Objects to Scene > Scene.001 and and delete the object from "Scene")
3. Select "Scene.001" and go to the world settings:
   
4. Add a new world
5. Set your render engine to Cycles
6. Switch back to "scene". You should notice that the render engine will change between the two scenes.
7. Link your camera and lights to "Scene.001" (but don't delete them from "scene"). You can now move your camera and lights around and they will have the same location/rotation/scale in both of the scenes.

Render both scenes with transparent skies. Compositing

1. Go to the compositor.
2. Enable Compositing Nodes
3. Add a new Render Layers node and select "Scene.001" from the drop down.
4. Add an alpha over node and plug them in so that one scene is on top of the other.

You will now have a Cycles object rendered in a Blender Internal scene.