How to play Guitar Hero Word Tour co-op with 2 keybords?

When i plug 2 keyboards they are recognised as one device. So I just need to make that Guitar Hero World Tour let me play 2 people with one keybord. And then I will be able to use two keyboards. I don't know if this is going to work. I think that here may be other solutions. So please tell me how can I play Guitar Hero with my friends wthout using guitars.