Sorry, Brady, I meant the second #4. I guess that you could make a combination cut of the top #3 and the bottom #4 but that would be really tricky and pretty hard to get the piece to match. If you hire a good carpenter, he might be able to give you better direction by actually looking at the problem. He will probably want to put in a waterproof glue with the nails to seal the end grain and hold the "dutchman" more securely.