Assuming that you have already analyzed how to presentd the information and those lists are the right way, there's only the presentation part left, which is what you are asking.
If you present empty spaces to the user, that generates expectation and doubts; the user may be wondering if something is missing of if he has to interact with that space somehow, so the best way is to only show what is relevant.
If you have a list, let say the item list, already visible to the user, and the sublist is not populated until the user acts on the item list, then don't show it, neither its borders, shadow or anything that tells the user that there will be something there.
On the other hand, if you can have other options, for instance select controls on the page, you can show all of them on the page, and use the right wording and design to show the user which one he has to use first. The advantage of this design, is that the user knows from the beginning how many steps the process will take. Of course you have to do the right programming to capture wrong interactions with the list.