NNTP - how to check for removed newsgroups ?

Hello all,

Simple question : using the NNTP protocol - How do I check for newsgroups 
that have been removed ?

I don't really want to go thru the list of all newsgroups I currently have 
stored and check, one by one, if I they are still present on the newsgroup 
server.

Remark: I found the command to find all *new* newsgroups (since a certain 
date), but have not been able to find its opposite.

Regards,
Rudy Wieser