Finally, after finding Twinbrook wouldn't load past 1 third of it's loading bar, and then after updating and getting the 0.0.0.0 bug, i've managed to get playing.

Made a new Sim, and right now she and two friends are living together.

One is a Firewoman, one entered the rabbit-hole medical career, and my main Sim the criminal career track.

Thing is, my firewoman always has to go put out fires alone. Despite the firehouse being full she is the only one who actually does her job. Then it occured, if all my Sims where firemen would they join her when she goes to put out fires.

If they where ghost-hunters would they all go out together and work together?

I've yet to try making a family that all do the same Ambitions job. So could sue some tips and info. If they can't work together i'll just leave them following their own paths.

I would like to know this as well. I'm planning to make a family of characters from the anime Ghost Hunt, and it would be nice if they could all do cases together.

Yep, my sim fell in love with and married a firewoman that she worked with. You choose the one you want to do the case and the other can tag along. The sim she married had a father who was also a fireman and eventually my two sims adopted and their son became a fireman. Had a little team of firemen and women solving jobs really quickly.

Yay! Now I can really have a Shibuya Psychic Research team. :D