Open Photoshop CS5 before launching Bridge CS6. Bridge CS6 will use the Photoshop that is running. (But this doesn't work the other direction: clicking on the Br icon in PS CS5 will not go to Bridge CS6.)
My experience on windows 7 systems.
I'm doing this right now on two win 7 64-bit installs. I've opened either app in different order and things work just fine. BR CS6 is fast and stable, PS CS6 is still too spooky for me (since its October and all )
Such a simple solution. I had actually done that already and was hoping to be able to have Ps5 open Br6 but I think that it is not able to.
It works for now so all good.