How to create VPN for remote user@domain details instead of ip

Hello, We recently moved from watchguard to fortigate . We previously had a vpn configured to a remote site through a domain user id (user@xyz.com) .So instead of remote ip address, it was configured as user id @ domain.   Could any one explain steps to configure this sort of vpn in fortigate. snapshot of previous firewall config attached   Thanks in advance.