Just like other address, Virtual IP addresses can be organized into groups for ease of administration. If you have multiple virtual IPs that are likely to be associated to common firewall policies rather than add them individually to each of the policies you can add the instead. That way, if the members of the group change then any changes made to the group will propagate to all of the polices using that group.

When using a Virtual IP address group the firewall policy will take into account all of the configured parameters of the Virtual IPs: IP addresses, Ports and port types.