Setting up a variable rent with an annual dollar cap

Does anybody know how to set-up a variable rent with an annual dollar cap? Our organization placed an annual dollar cap in one of our leases. The annual cap is placed at 100k. We cannot charge variable rent once the 100k cap is reached. Here is our requirements:

Monthly billing and calculation

3% of gross sales

100k maximum annual cap

No proration on partial years

Thanks in advance for your input