Make some extra changes for displaying your rules on each forum.
In few steps you can make this:
Thanks to this plugin you can:
set three buttons with links and own names
set font awesome icon for each button
set rules title for each forum
set render the image to make rules more visible...
When XenForo needs to test something (user/page/post...) against some user-selected conditions (criteria), it uses the Criteria system.
Some places, where the Criteria system is used:
Addons can also use this system.