How to configure more than 2 failover group in ProxySg for redundancy.
For redundancy, you can configure a maximum of 128 failover groups (unique 128 group IP addresses) on the ProxySG. See article How many failover groups (SGRP) can I configure on the ProxySG?
Prerequisites: See ProxySG High Availability/Failover fails between Proxies located in different networks
First you have to setup same virtual IP address on all appliances.
You must decide which machine is the master and which machines are the slaves, and whether you want to configure explicit proxy or transparent proxy network. The ProxySGs can be deployed either in parallel or serial mode
When configuring the group, the master and all the systems in the group must have exactly the same failover configuration except for priority, which is used to determine the rank of the slave machines. If no priority is set, a default priority of 100 is used. If two appliances have equal priority, the one with the highest local IP address ranks higher. In this case master should have Highest priority, second slave should have 100, and the third one priority lower than 100.