How to re-route existing path?

I got a closed path A on one hand and on the other hand I have a path B made of 2 anchor points.

I would like to pick an anchor point in path A and make it that the next anchor in the path is one of the anchor in path B, then it continues to the second anchor in B and then it comes back to what was the next anchor in path A.

The handles from B would have to be preserved.