Not really - nothing happens if I press the down arrow. It does not offer more than 6 results.
Yes, this is what I advise folks. But this only works if you already know what you are looking for. There’s no way to see what’s available without guessing.
As of now I’m recommending keeping a list of groups that I provide. This is also handy for mentioning people when posting by email, so not a bad idea in any case.