Benefits deductions over 9 months

We have certain employees who only work 9 months a year. They are in their own Salary Basis of 9 months, but in the same payroll definition as everyone else (those that work 12 months, and expect deductions over 12 months). I did find one suggestion, but I'm curious on how others may have done this. What is the best way to have rate deductions spread out over 9 months (we have weekly, biweekly, and monthly payrolls) for some and 12 months for others? Thank you in advance!