suggestion: auto-group hibernated tabs

Excellent extension, a small suggestion - in my case I rarely need to access "Last Session" or "Hibernated" tabs, and close them all from time to time, but do want to keep them just in case. They tend to crowd out the current Window tree, so I close them all in bulk from time to time. It would be nice if they were automatically grouped as one at the top, and then labelled by timestamp within
e.g. so the frame has at the top
> Last Sessions
[which expands to]
> Last sessions 2015-09-17.. (n pages)
> Last sessions 2015-09-16.. (n pages)
[etc]
> Window (n pages)