To be honest I only got these conversations 1 to 1, with reasonably close friends (i.e. we know each other for several years, meet regularly, e.t.c)
To get there, make friends. Work on those relationships, indulge others despite the fact that they might not think before they talk, have big egos, and don't really want to be challenged ... you can survive i.e. one boring/weitd conversation over lunch right? :) Maybe after few rounds of conversation you realized you clicked with the other person and then you start going for coffe breaks, discussing geopolitics or something. Maybe others join you ...
... in general it is improbable that you will be just handed a group of people that just fits, and even if you are so lucky, people and group dynamics change.
Apart from technical forums like this, one thing 'Id add that I'm seeking, personally, is all of what you said + a willingness to enjoy life and not obsess over work. A community where people find enjoyment in talking with others as opposed to just bragging about what they did when they weren't at work would be a plus.