This is somewhat cool, but the use described in the original post is very limited in that only two levels can be connected without a bit of strangeness.

There are two ways of going to a secret level in jj2. One way is by using a bonus sign post. The other way is by using a normal secret level event. The bonus sign post works like a normal level switch and is the best (if not the only) way of properly doing multiple exits in jj2.

The other method makes jj2 consider the level you arrive at an actual secret level, and as soon as you hit a normal end level event it will return you to the warp secret event you got there from. You can use bonus level signposts to proceed to ther levels, but jj2 will still consider them to be secret levels, and as soon as you hit a normal exit you are back at the first level.

So in other words you can either have two levels connected with this method, OR you can have an extremely weird and useless chain of multiple levels.

I am currently working on a different system that can connect levels "metroid style" which would be a bit slower and a lot more effective. I'll probably finish it tomorrow.