Sharpen - except at the edges.

Hi all!

I want to sharpen the entire image except at the edges.
With the edge Detect tool, you can select the edges (high contrast spots) and edit them in all sorts of ways.

However, I could not figure out how to use this tool to select all the edges that I want and simply mask them out.
How can I do this?

Thanks in advance.

You can maybe try a LumaKeyer and a Bitmap node?