Configuring Complex Load Balancing Scenario

Are you saying that for example, you want cluster B to remain active even though cluster A may come back "up"?

If that's the case then i would do something like assign health monitors at a pool member level and i would configure the monitors that get assigned to the members in cluster A so that manual resume is enabled, that way you can return cluster A to being active when you desire.

Or i could have totally misunderstood your requirements :)