In the other question I explained how to use an (if:) macro to conditionally show content, and also how to check if the current value of a Boolean based story variable was equal to false.
Use the current state of each of the three variables ($seen1, $seen2, and $seen3) to determine if the related link should be shown or not.
(if: not $seen1)[ [[Passage 1]]<br>]
(if: not $seen2)[ [[Passage 2]]<br>]
(if: not $seen3)[ [[Passage 3]]<br>]