To actually declare or tag a logical group of attachments (or other elements), regardless of their location in the Hierarchy, and see that group as a different element on which you could operate...? There's nothing like that to the extent of my knowledge.
The only thing that comes to my mind to do something similar would be to select those attachments and save their selection by pressing Ctrl + <number>. Later on you could select them again by pressing that number, and use the key 'H' to toggle the visibility of them all.
Not exactly convenient as you would need to memorize the number and reserve it for that purpose. The good thing is that they're saved between sessions.
My suggestion is that if you're using interchangeable attachments that could share the same bone/s, you also put them all in one slot so only one of them is activated at a time. And if you can't do that, then I'd configure the setup pose to hide them all once, and only when animating showing the ones you want visible at frame 0.