All 8 conferences follow the same structure.
The bottom of the pyramid has four leagues. The next stage is comprised of three leagues and promotion and relegation works on a 3 up 3 down basis except for in the bottom divisions where four teams go down and the top divisions, where only two teams go up.
The final stage is the top of the pyramid, with only one league. In division 4, a total of six teams will go down. With this system, it is possible to progress from the very bottom division, to the top of the conference in eleven seasons… if you've got what it takes of course!