You will have to cut the rind by hand. There is no way a domestic grinder can grind a rind, as long as you do not cook it for several hours first. I have one of the most powerful domestic grinders there is, and it does not do rind. Period.
You'll have to cook it first for several hours, and then the whole point of adding rind is lost, as far as I can see. You can cut the rind into small pieces and add it to the mix when you stuff your sausages. I have eaten sausages made with rind added, and the rind adds deilicious chewey parts.