Chapter 9 High Availability : VRRP : Adding a VRRP virtual router to a FortiGate interface : Using a Second Destination IP (VRDST)
  
Using a Second Destination IP (VRDST)
VRRP can now be configured with second destination IP (VRDST) for monitoring. When two IPs are used, VRRP failure will only be reported if both monitored IPs are down.
Use the following command to configure a second destination IP (VRDST) to port14:
config system interface
edit port14
config vrrp
edit 12
set vrdst 10.10.10.20 10.20.20.10
end