Not an expert on Juniper but having all interfaces in one redundancy group has always caused me problem, even if you want an Active/Passive setup the RG's are controlled by the node priority, just set the node you want as active to a higher priority then the passive node and all the interfaces should stay on the active node.
What you got to think of is if you have 1 link goes down to you want all your interfaces to move over to the Passive node, if you do then go with 1RG, if you don't then put all the interfaces into different RG's.