Hello - wondering if anyone can help.

I'm planning to cycle from John O'Groats to Landsend next month, and am trying to get my bike ready for it.
I've got a Langster & a tri bike. I think it's too hilly for the langster, so I had planned to use the tri bike with p-clips and a seat post clamp with the extra bit for panniers to attach to, but just tried to put it on, and found that the bit on the frame at the back that I thought I'd be able to clip it onto, is carbon.

Does anyone know if it's possible to move the gears from the tri bike onto the Langster?

I'm not sure how well I've explained it- my terminology isn't brilliant, but if anyone has any gems of wisdom, let me know!

Thanks