Convince toolpaths to ignore outside edge of an .stl?

As part of a manufacturing template, I am looking to carve a 1/8" deep dish with approximately 2" radius (curving for about 1/2") in the middle of a piece of wood which seems to be something that CNC is not particularly adept at. One of the options I am working on now is creating a .stl file and importing it, but it seems that Easel’s tool paths always want to carve the outside edge, even if the outside edge matches the material perfectly. For example, if I make the .stl of an object that is 6"x6"x3/4" with the dish I want and set the Easel material to match, it still wants to “carve” the outside edge.

This currently leads me down a problematic path, as the detail file for the ball nose bit unnecessarily traces the outside of the 3/4" block even though the rough out bit has already cut it perfectly, and since the detail bit shank starts a little under 3/4", the shank bumps into the material and chaos ensues.

Is there any way around this, or should I look at a different method? I have considered creating and importing grey-scale, or manually adding a number of circular vectors, but neither of those methods seem to allow for use of a ball nose bit to cut the curve, not super excited about the manual carving and sanding implications.

Any thoughts? Thank you in advance!