@tshrinivasan first time somebody else asked this!
I have currently 90 classes, since 2017, as approximately I held a class once/twice a month, so I currently I have 90 #Telegram groups. A group = a classroom.
Each group/class held a topic. So I have individual class for each of #FreeSoftware Introduction, Libre #Hardware, #LibreOffice & #OpenDocumentFormat Importance, etc. materials.
Classes are sequential, so once a class with a subject finished I create new class with another subject.