Once you designed the part, it could be cut with a cnc router with rough cut first, then finish cut with a ball end bit/mill fairly easily, but may take a bit. You can also use standard router bit in your cnc spindle/router. But in my opinion, there are times when simpler techniques are faster and easier. In this case a couple of appropriate router bits and simply using a hand router or router mounted in a router table would accomplish your goal in a lot less time and effort (and material) without all the design, setup and fixture/clamping effort. I know... the cnc router is more fun, but...