How to only use sub primary tags?

rickusbstick

The issue

Hello all,

I have created an forum and am really happy with how this system works. But i really would like to have the following.
As seen on my screenshot below, i have a few categories, and i have sub categories under them. You can see it like how an old school forum works. I just want my users to choose an sub category to post in and thats it. I want the system to just need the sub primary tag to work with. I dont want users to post in an head category alone. How is this achievable? I tried a lot of things but i cant figure it out.

So in short: I want people to choose an sub-primary tag to post in. A primary tag should be an collection of possible sub primary tags to post in.

screenshot:
https://prnt.sc/8oPy0Zx0rCxt

Flarum information

Flarum
1.8.13PHP
8.3.30MySQL
10.11.15-MariaDB-cll-lveInplanner
syncSessie Driver

ernestdefoe

They have to choose the primary tag. In the tags settings in the Admin area set required primary tags to 1 and 1 and requires secondary tags to 1 and whatever else. Then the user is required to select a secondary tag.