Would be a neat feature to be able to collapse groups and hide many shaders. Maybe chaining out all the inputs from the bottom of the group when collapsed.
Just select them and hit "d". :D
Oh well that just disabled the group and shaders. I mean collapse it to just it's title bar, not effecting shaders.
Someone has already done this (as far as I understand what you're asking for) and shared some complex Fake stones setup inside a shader. I have no idea how to create something like that, but I just deleted the contents of this grouped shader and added a simple surface layer that's connected with the internal child input. Otherwise it seems you are losing the internal inputs. You can delete it later.
You can put any shader setup inside and everything looks tidied up (unless you open this grouped shader...)
I have seen you can put shaders inside a groups internal node network, is that what this is? I'll have to take a peak.