Is there a way to have a global 401k Employer match maximum?

At this time, Namely cannot support a total annual maximum based on a combination of more than one deduction code. The max for employees contributing to pretax and Roth must be monitored to ensure it is not exceed.

You can choose to enter maximums on an individual's deductions. If you go this route, Namely recommends splitting the annual maximum across the 401k deductions 50/50, i.e. set half of the total maximum on the Pretax deduction and half on the Roth deduction.