Most of my networking has been done in specific areas of information management - for example, my last role was in careers information, so I was part of a regional network. It was useful to find out what others were doing in the region's services, and thinking about where the service I worked for ought to be going.
I'm now part of the CILIP chartering group (which is actually an online network, so I guess it doesn't really count!) but I do find that useful. I keep an eye on that for any group meetings, but so far have just had access to the email group. I've also built up a relationship with my mentor, whom I didn't know very well before chartering, and she has been very supportive despite a heavy workload.
As haven't so far come across a group for librarians working in alternative roles - perhaps there aren't enough of them yet, or perhaps there are simply too many 'alternative' roles to make such as thing practical. I'd be interested to hear what others think.