Public WiFi access portal with Guest tracking.

I want to set up guest access at a local church parish for parishioners to use while on the grounds.  But I want a way to track who is using the service, for security logging and use tracking.  Creating static accounts is not practical.  I'd like to use some sort of guest portal to gather email or SMS and have it verified and pass along their temporary password, via their email or SMS, like I have seen at other places.

I have looked through the Fortinet documentation and videos, but do not see anything like this.  Is this possible and what is needed to set this up?