We were doing some work for our selves, you know you over hear a rumor and go for it with out a Johnson footing the bill. Well another group of runners were already being payed to do the job. We just heard the trickle down from the leg work our other chracters did. The other characters got the underworld in a little buzz about something big going down. The first runners didn't have a dedicated face so a few of our etiquette checks didn't go so well. The other group, the newer group was just beating bushes looking for some extra cash and ran into some info. If it wasn't for some inter team argueing and arriving at a site on full alert we maybe would have stumbled onto a run in progress. It was just something the GM thought would be fun.
In one of the book adventures, I am not sure which one, and I don't want to know, because I hear it is only the beging of a set of runs and I am a player in it. A team is hired to help take out the power grid? Well a year or so before (we play a year or so behind the canon timeline to allow things to work out across several groups of characters and we don't like the metaplot sneeking up on us) at some of the other characters hideout we were sitting around doing downtime things and the power went out. We had a pick up game of "lazer tag" in the streets, funny watching professional killers play lazer tag with kids, they had no idea what hit them.

Well a few months later in real time another group of our characters were the ones who pulled the job.
We have a time line and key points mapped on it so we can keep track of who did what and what time it happened.
Like my third longest running character has a small arms running ring, he is semi-retired, he only does runs that certain "friends" need done. The funny thing is they (the new characters) are in his bar all the time, it is right down the street from their "team" house. Well during the mob wars he helped a "friend" out with some guns and things. Well the new team we are playing befriended an associate of my character's and they get guns from him on occasion (availability and all) but they see the build up to this "favore". It will be funny when the new guys hear about it in comeing weeks.

We have a blast linking all the runners together, we always thought even though runners are plentyful in Seattle it would still be a tight knit group. People know each other, stuff gets around. Now some characters have never met others, some hang out crossing the generations if you will, and on a few occasions some characters have killed the others, some characters that killed the others belong to the same person, like character A meets character B of player 1. Stuff happens and character B dies a very bloody messy death. Yes, you need a score card and map to figure it out, if you want to, most times it never comes up. We don't always bring old and new characters together, it depends on all the circumstances, like what style the character has or diet, or hobbies.