How to create a non playable league

Hello,

as I am creating a custom database for myself I came to a problem.
The first three tiers of the league system are supposed to be playable and the fourth tier is meant to be a filler tier, so when the teams from Division three get relegated, there will be teams promoted from the fourth, non playable tier.

How can I do this.

Greetings
Rennsemmel

there's a tick "League Type" or smthn like that in league's general options, there you can choose Non playable league.
If no one will correct me, I'll make a screenshot in the evening.