Is the option to choose "does not contain" there? so it would read:
Machine Type does not contain Windows
No... the only options I can choose are:
You will want to look at custom properties, they are designed for this - your network is static, the things being introduced are not. So you introduce a custom property to either filter a: only the new things which won't have it, or b: only the things with the custom property.
In one of my Customer's site I had a very complex setup.. Where I used this logic.. Whenever a node is added I have asked them to make sure to fill the correct custom properties(I have restricted with a drop down).
Then I have set up groups using Dynamic Query. Which will automatically add nodes with custom properties ABC to group ABC.