You are definitely making things harder on yourself unnecessarily, bongobeat. I am only saying that because I care about your mental well being buddy lol
In my Myst Demo I had some Placeholder levels named: Stoneship, Channelwood, Mechanical, Selentic, Rime. After I published the current working Demo, I took a small break before working on the final product. When I got back to work, I ended up created several level "add ons" to my Stoneship Map. Each and every one of these Stoneship add-on levels are sitting under the Rime level in my Editor. Why? Because if I try to move them up next to the actual Stoneship map, a lot of Teleporters and certain scripts would suddenly need to be fixed. And there's just no reason for it. Making the Mod would suddenly become frustrating and the only thing I would gain is... not having to use my mouse to scroll down a bit.
In your case, I assume because you have a large number of levels that you want all of them close together to make Mod'ing life a little easier to manage, however, you are better off just using a pen and paper to keep track of which levels are connected to each other. This might be a good time for some self-reflecting, to evaluate level consolidation. Sometimes, less is more