I'm assuming you have your blocks randomized already. One way to do this would be to put each of your 3 randomized videos on their own page and randomize those pages. You could then write a pre-skip instruction on each page to skip if that equivalent page(video) was seen in one of the other blocks (i.e. Preskip to next question if Shown (Q1A) or Shown (Q1B) or Shown (Q1C) ). This would be an example for Q1D, assuming that 1A, 1B, 1C and 1D were the same video question but in different blocks.
You could also use a combination of quota questions and list building where the items in the list call upon the 3 different video scripts, but this gets a little trickier. I just did something similar recently for showing images.