@smccloud Ugh! I didn't realize that was a limitation. Thinking about it though, I understand it, but I certainly don't like it.
So if this is important to you, then you're going to have to split out the MX into it's own network. You can do this from the Organization overview page. check the checkbox for the combined network, and the hit the "Split Networks" button at the top.
BIG FAT DISCLAIMER: I've never actually done this myself, but I know others who have. It might be best for you to test it on a dummy network first, or in a change window .
Edit: Haha you removed the picture. But I did see it 🙂