Branch dimension nether

So we all know how you can get to the end island after fighting the ender dragon. What if you could branch something else into the nether like the end islands? Like after killing the wither you could find a portal type thing that would bring you to a different type of nether like level 2 nether where this new nether has biomes and a harder wither boss and it could keep getting harder until level 5 nether.