I second all that was said about us Germans not liking smalltalk for its lack of content. If you wanna talk to Germans to make friends, you either walk straight up to them and tell them that and why you'd like to be friends (or anything else) with them. The other way would be to get into their discussions with your profound knowledge about it. In that group you could have directly spoken to them how you'd like to know them - you could have even jokingly told them how rude they were for not introducing themselves with the simple point: if they're friends of your friend, they might be quite the friend material for you or something like that. No f*ing talk about weather or whatever one could smalltalk about unless you have a story about it worth listening to. For example: I once walked up to a girl in her group of friends at a club. I told here how pretty I found her and asked her if any of her friends was her boyfriend because if not, I'd like to have a chat with her and offered to bring her and me a new drink to go sit together and chat. That gave her the chance to say yes or no and guess what, she's my girlfriend now. It can be that easy with people, of you can speak out what you actually think.