Time Sync issue on Application Servers

Hi all, currently we are still having the time sync issue for this time-sensitive and we have an idea to use F5 to resolve the issue.

Current setup on F5 is the traffic are on Round Robin Load Balancing Method to both application server.

Proposed Solution is to point the traffic to one application server but we still want to have the other application server as back-up.

Should I use Priority Group putting one of the server as Priority Group 2 and another as Priority Group 1 ? What Load Balancing Method should I use ?