Did you try putting "Right Arm" as the third child of "RA Triggers"? Then you have an independent group for "Right Arm" without all the other cycles in it, but picking a trigger would hide "Right Arm".
I personally don't know a way of automatically hiding a group with triggers other than them being siblings. I think its more a matter of getting the tree and independent groups organized "just right", like you have been trying.
I tried that but still have the problem.
Looking at Show Mesh when the cycle layers is in the Right Arm group all of the arms show no matter which layer I click on. Its a real mess in there and I can see why the drag function is confused.
What I am doing now is adding the trigger groups to the Right Arm group, setting up the cycle layers and triggers and then recording those moves. Then I am removing the trigger groups from the Right Arm group and recording the drag arm movements. A hack but it is getting the project done.
I can't help but think I am doing something wrong or there is a work around with the layers order. If not then this is a bug and should be fixed to allow the full set of options for the arms etc. Would be nice if you could hide another group outside of the trigger group in addition to hide others in same group.
Even recording the drag movements with the triggers removed and then adding back the triggers interferes. Maybe you just can't have both options simultaneously for a characters arms?