Playoff Question

[Florian von Saltes]

I have a question, what would be the way to activate the following classification in the advanced rules:
Competition of five groups the first ones are classified for the superior division, the second ones are classified more the third best classified for playoff eliminatory of three squares to ascend.
It would be like implementing the question: the third best of the five groups.
It will be done if the competition is designed as generic groups, but this case the leagues are simultaneous competitions since they depend on a higher competition with more number of leagues.
Thank you very much.