Sort of. The YC founders are a pretty cohesive group, so if you get into their circle you get a lot of the benefit. This goes for SV/SF based startup founders

Sort of. The YC founders are a pretty cohesive group, so if you get into their circle you get a lot of the benefit. This goes for SV/SF based startup founders generally, too. Since it's such a closed group, if you make friends with people at one meet up you'll end up expanding your circle to several. There are some open meetups (e.g. Hackers and Founders) and also meetups on technologies (e.g. SF Javascript).