The phrase "different rules" means that two or more situations or people have separate guidelines or expectations for how they should behave or be treated. Full definition
There was still the option for different rules for different classes... but they didn't take it. (law.stackexchange.com)
Judges may not base their decisions on a parent's gender when deciding custody as part of a divorce litigation although different rules apply for unmarried parents. (info.legalzoom.com)
However, as you may or may not be aware, many poker sites have different rules regarding whether players can sign up and play dependent on the country they are based in. (myintimcity.com)