merge two spines into one

Hi Guys! I am modeller not a rigger I have to say it before judging ;) I just found this forum and hope you help me. This is my first rig ever the purpose as a game model. Please share with me your opinions aside with that in mind. But straight to the problem, I stuck trying to merge/follow second outside spine rig with one inside the mesh don't know how to bind them that spine from outside follow all movement when the spine inside body moves. I`am not sure if its good approach at the end maybe other solution would be better. Thx to anyone who will help me wit problem. I attached a link with maya scene https://drive.google.com/file/d/1cPL_B2h416eLgS43HGafjyFwrdq24Y4x/view?usp=sharing