Hi Guys! I am modeller not a rigger I have to say it before judging 
Ive just found this forum and hope you help me. This is my first rig ever the purpose as a game model(the rig will be slave rig not included yet) Please share with me your opinions with that in your 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. Iam 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