Maybe people can add to this for other clients :)
HTH this helps people using tin.
Back in the day - 2002 or so?* - there was this dude Blinky the Shark
whose "Usenet Improvement Project" collected the necessary info to
block GoogleGroups no matter which Usenet client you used. He died
around 2012 or so as I recall, but someone keeps his info alive.
http://twovoyagers.com/improve-usenet.org/
The info for TIN is here. Slightly different than your approach but there's more than one way to get what you want I'm sure:
http://twovoyagers.com/improve-usenet.org/filters_ex3.html
*Take all my dates with a grain of salt. Not worth being more precise
and too tired/lazy to look it up.
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)