Hi Christophe,
Thanks for your answer, sadly it does not solve my problem.
What I am trying to do is the following :
Setting the object on "Show on relevant stories" (montrer sur tous les étages appropriés) and having the 2D symbol show on relevant stories depending on the height of the object, but not on every stories.
I already have a workaround which consists on setting the object to "Show on all stories" and not drawing anything on certain stories but this technique is not perfect because even though nothing is drawn on theses stories, you can still select (and move or delete) the object, which is dangerous.