It's also possible to create some fake borders (I have not included any border markers at this point) but with a bit of work it should be even possible to "fake" border push back for neutral nations. Sadly those restrictions are not checked periodically but only when a military building is finished in a certain distance forcing a border update.
This still allows you to maybe block a path by "Neutral Tribes" and also block a certain spot where the player then, after the "Neutral Tribe" decides to help, build a military building, forcing an update and finally having a path.
As RestrictedAreas are currently not working as expected, it's quite hard to create a good looking map with all needs to combine a good looking gameplay and map.
But, that way it should be possible to do quite a lot (which might include some graphics and a lot of work then) but I'll build Two RttR missions including things like:
Decisions, either good or bad, where the player also actually sees the result of his action (got some ideas for that), maybe some small riddles including a bit googling for information you don't know yet, or maybe you do. Also I think I'm able to fake a bridge, but I that will some more research, testing and graphic works (as I have to fake water, which is moved and makes it quite hard in that case because I have no idea yet how many frames water uses and at which speed water is animated).
If anybody is interested in how I did this, here are all files needed to test this on your own system.
Please note, this is not an official feature. Also the Updater won't work anymore as he wants to rewrite the actual MAP_0_Z.LST and not a directory.
Also note: Those graphics are actually taken from screenshots of Heroes and Might and Magic... so I think that can't be a problem as they are officially released.