AWS Multi Nic F5 - config sync across Availability Zones

Hello , 

i am in the process of creating 3 F5s in 3 AWS - AZs . and i am following below document .

Question - if the 3 devices are configures n 3 different VPC subnets the They will have different VIP ips .

what will sync in a sync only group ?

https://clouddocs.f5.com/cloud/public/v1/aws/AWS_configsync.html