thanks for letting me know it’s a tool. i’ve added it as a shortcut to Paketti, and it, yes, does definitely feel like it should be there by default 
another “I can’t believe Native Renoise doesn’t have this” moment.
also @Jonas thanks a lot for pointing me to the tool, since i can now do the “Pattern Matrix” selection idea posted in the thread:
New Tool (2.8): Selected Tracks To Group - #9 by joule by @joule
and i already, last night, fixed the “errors out if master or send track is selected” because it made sense (your report i saw on made me smile since i had already thought about that error New Tool (2.8): Selected Tracks To Group - #8 by Jonas )
anyway, interesting stuff. also noted i need to preserve group state so if i select this:
it shouldn’t end up like this:
nice. i’ll first tackle the pattern matrix.