The phrase "a separate set of rules" is correct and usable in written English.
You can use it when referring to distinct guidelines or regulations that apply independently from others.
Example: "In this organization, we have a separate set of rules for remote workers to ensure productivity and accountability."
Alternatives: "an independent set of guidelines" or "a distinct collection of regulations".
Though it wasn't noticed, the SEC on the same day proposed for comment a separate set of rules that, if adopted, could undermine the general solicitation rule it had just voted to approve.
The AMT is calculated by using a separate set of rules that disallow many deductions and exemptions used in computing traditional tax liability, including state income tax or second mortgages, and because the taxable rate is not subject to inflation, over the last several decades more and more middle class taxpayers have been subject to it.
You cannot create a separate set of rules for yourself.
Last year, employers won one round in the H-2B fight by appealing to Congress about a separate set of Labor Department rules on wages in the program.
In the letter to Mr. Lew, the senators say that to avoid confusing the banks, the C.F.T.C. cross-border guidelines should not take effect until the Securities and Exchange Commission completes a separate set of derivatives rules.
It's also possible to own real property inside an individual retirement account, which my colleague Paul Sullivan wrote about last year, and which is subject to an entirely separate set of rules and regulations.
All but one of the agents are already regulated under a separate set of safety and security rules governing "select agents".
Add to that the separate set of rules within the Scottish Football Association about its members' directors being "fit and proper" people.
A 1999 S.E.C. rule established a separate set of regulations for alternative trading systems, which have grown to 29, from 10 in 2002.
In order to rule out carry-over effects during repeated trials, we tested a separate set of five mice repeatedly at a singular dose (4X) over five days.
