I am wondering if Front Door would actually be a better service to use in this scenario for you. Have you taken a look a the front door service to determine if that is a better fit in this particular scenario? Let me know and I would be happy to answer some additional questions on Front Door but to me that seems like the better fit here.
Hi @EduLorenzo, I am curious why you've architected your site this way? Is it that you see more traffic for a certain sub-site from a specific region? While Azure front door will support this config (check below link), isn't this something you could do via DNS routing by mapping a specific subdomain to a different IP?