Hello Evelyne! Are you basing your loop and merge on any other question that has all the videos?
Because the solution would be hiding those videos from the original question and you create your loop and merge based on the "options"(videos) that were displayed on that question.
But, as I was saying, the loop and merge would have to be based on some other question options :)

No, I am not basing it on another question. I have all my videos in a field of loop and merge in the question itself.

Any ideas IsabelPosada_Voce or ahmedA, who helped me with my previous loop and merge question.

Why can't you just delete them from the L&M config?

ahmedA
If I do that, the cell will be blank which results in an error when this cell is chosen. Furthermore, if I replace the order of the cells, so no blank cell exist, the order of the results will be changed and this will make the results invalid.

What you have described will only happen if you have pre decided the videos you want to show to a particular group. In such a scenario, you might consider splitting up the L&M into multiple block. One for each group.