Window tab subgroup collapse / restore?

Hi! I'm really liking Tabs Outliner, coming from FF's two very powerful vertical tab addons. I believe it's much more powerful and works very well preserving resources. I'm curious, since I haven't been able to find a way, if a particular subgroup of tabs under a window can be killed / restored as a group. So, under the main window if I have:

├─ Window
   ├── example tab
   └── foo
       ├── bar
       ├── bar
       └── bar

I'd be able to close the foo tab and its children by using its save & close button. Then to restore it and all its children, I double-click foo. The whole time the "example tab" remains open in the window, it's just the foo/bar tabs that are removed and re-added appropriately.

Is this currently possible? If not, could it be?