How do I filter unlocked and unique segments?

So first it has to be unlocked, and if the segment is unique (only 1 occurrence), display it, if the segment has another or more occurrences, display only the first occurrence, how do I do that? Repetitions - First Occurrences won't work since it only display the first occurrences if the segment has duplicates, i.e. it does not show segments that is unique. An example: for segments A, B, B, C, C, C, show me only A, B, C.