1. Remove the portal that's in the cave before making your way towards your main portal at the village. You'll need to get the X & Z coordinates of its location. 2. Once you did, divide the "X" coordinate by 8, then divide the "Z" coordinate by 8. That will be your new X & Z coordinates that you need in the Nether. 3. Thereafter, travel to the Nether and destroy the current portal you spawn into. Rebuild it at the new coordinates that you got and your portal should link properly.