Linking map and map sections

When creating multi-level maps, it can get quite confusing to know which path leads to where. Being able to select a map point, such as a set of ascending stairs, and connecting that to another map point, e.g. the corresponding descending stairs, would make this process much easier; it should also be possible to do this across map files. When doing such, it should also be possible to section off a map area, such that you could get an overlay (for example wireframe) of that area to work with, knowing which parts leads to where, which parts are above what.