I want to make a promotion playoff so that those teams that ended up higher in the league table make it to the next round if there's a draw.
e.g:
2º TEAM A
3º TEAM B
4º TEAM C
5º TEAM D
Promotion play-off: TEAM A vs. TEAM D. If they draw, TEAM A will move into the next round
In case you're wondering, this does exist. Promotion playoffs of the Argentinian second division are going on right now and they work like this.