Returning a boolean value via Power Query M with data from multiple columns

[love]

 Hello.

I would like a custom column to return a boolean value depending on the data in other columns.

Example: If all "statuses" from one "milestone" are either "done" or "Dropped" the costum column should be TRUE. If any other status for a given milestone is present, it should return FALSE:

How can I put this into a Power Query M formula? I am stuck on how to query multiple rows (milestones) to be a variable for my custom column. Is what I am asking for possible in this data structure?

Thank you!

-anon