The phrase "a special set of rules" is correct and usable in written English.
You can use it when referring to a specific collection of guidelines or regulations that apply to a particular situation or group.
Example: "In this game, players must follow a special set of rules to ensure fair play and enjoyment for everyone."
Alternatives: "a unique collection of guidelines" or "a distinct group of regulations."
A special set of rules had been agreed for this prototype mixed martial arts fight.
If you ever share personal information with friends online you probably already use a special set of rules to determine what to reveal and what to keep secret.
Mr. Levin said for the first time Wednesday that it may be worth creating a special set of rules for the small number of cases in which generals or admirals are accused of sexual assault.
Each year, hundreds of thousands of migrants are picked up, fined, sent home or forced to work under a special set of rules that are outside normal criminal procedures.
No longer do they assume as they once did that a special set of rules applies to him, and that they would be punished for trying to mimic his behavior.
Fielders play knee-deep in the shallows, and a special set of rules will allow the winners to impose their choice of Devon-style jam on cream or Cornwall's preference of cream on jam on the scones, served at a celebratory tea, back on shore.
Passover has a special set of kosher rules that include no leavening or flour and require complete kitchen cleansing for an establishment's food to be certified "kosher for Passover".
While it's unfair to misinterpret what is in essence a perfectly nice gesture, like many gay men I'd rather not be treated with a special set of "gay" rules in my relationships with straight men.
As a background matter, foundations must follow a special set of tax rules in order to avoid certain penalties.
Our reporting on the best- and worst-selling cars features a special set of ground rules that make our list more than something one could find by reading individual automakers' sales reports.
In the slide show that follows, we report most manufacturers' highest- and lowest-selling vehicles in the U.S., but with a special set of ground rules that make the list more than just something one could find by reading individual automakers' sales reports.
