Ok, but I don't understand what policies you are testing, Layer 3, Layer 7, bandwidth?
As I understand it, you must create a different group policy for each iPSK, according to what you want to apply for each one.
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
Please, if this post was useful, leave your kudos and mark it as solved.