Change LB priority based on status

Hi I need help!

Load balance traffic between server A (IP: 1.1.1.1) and server B (IP: 1.1.1.2).
When server A goes down, traffic should be sent to server B.
Even when server A comes back up, traffic should be sent only to server B until server B goes down, and no traffic should be sent to server A.

The same thing happens in reverse.

When server B goes down, traffic should be sent to server A.
Even when server B comes back up, traffic should be sent only to server A until server A goes down, and no traffic should be sent to server B.

Is this setup possible in F5?

 

thank you