Well...by the group made on WLM isn't possible, but recently was released a script to make a list to block some contacts... So... In the first situation, I
THINK it can be done by a script like that. You just add the people of "co-workers", following your example, in the script and when you (don't) want to take notifications about them, it's just to run it (turn it off).
But you're going to need to wait someone else.. I just gave an idea...
About the rest, you are going to make changes manualy on Plus! Preferences...
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