How to sort Tab Groups in Safari 15

The new Tab Groups feature is great. It's much quicker and less cumbersome to create groups and move tabs around within and between them than it is to do the same using folders in Bookmarks.

I hoped it would let me get around a big frustration of Bookmarks—the inability to sort folders and subfolders alphabetically, except by dragging and dropping. That gets to be incredibly time-consuming when you have as many of them as I do. (To be clear, I mean sorting the folders, not the pages within them.)

Is there a command that lets you sort tab groups alphabetically (the groups, not the tabs within them)? Or does this new feature have the same limitation as Bookmarks?

Also, can you create subgroups (equivalent to sub-folders)? So far, I've been creating empty "spacer" folders, so that tab groups in effect become subfolders and I have at least a fighting chance of finding what I'm looking for. How that will work out as I add more and more pages remains to be seen.

Thanks in advance for any information or suggestions.