F5 load balancers - Two HA pairs across DCs

Hi all,

Trying to run through a design in my head.

Assume there are two DCs, a primary and a backup DC.

There are a pair of F5s at each DC in a HA configuration.

If primary DC goes down, am I right in saying that routing traffic over to the other backup pair at the other DC is going to require a route change and/or DNS changes and that there is no configuration that can be done on the F5s to "link" these two HA pairs together

Thanks