Create a Fiscal Quarter Field

Hello - 

I need to create a dashboard for our executive team and they want it to be charts by fiscal quarter. Our fiscal quarter is off by one month, so for example October is Q3 of 2021. I know that in reports you can group by fiscal quarter. My challenge is that I need to total two fields and create a formula field from them. They want to see login % by FQ, so Total Logins/Active Users in total, not by customer. I can do the sums in of each but not eh % in a report, so I was trying to create a FQ field on my snapshot table to use in data designer, but I can’t figure out how to convert the month and year to a FQ field, i.e 3Q 21. Any suggestions? Thanks