Balancing Methods and Priority Groups

Here's a scenario: In a situation with a two members pool for which it'd be desirable to maintain all requests to a primary system, and only fall back to a secondary in the event that the primary goes down. The reason for this is the application does not share state and sending requests to one system is desired. This would mean, that once a switch over happens, the LTM should continue sending to the 'active' member.

My initial thought was to use the priority groups and assign those nodes appropriately. My concern with this is when the defined higher priority member recovers, it then is activated because of its priority, which it'd be desired to stick with the current active.

I have considered not using priority groups and thought about simply disabling one of the members, as well, but this means manual intervention for bringing the secondary member online which is not desirable. I'm also not seeing a balancing method that would indicate 'stick to one', since that's not really balancing. I'm not opposed to writing an iRule for a solution (i.e. change the priority level of a member once active, if possible), I just was thinking that someone may have came across this scenario before and their would be a system level solution.

Thanks for any ideas here.