you can have 2 sims at same active career?

Yeah, I had two doctors in a household. When you go to work with one of them, the other one doesn't show up, even as an NPC. Well, no, one time the other person did show up as an NPC for a shift change, but they got stuck on the sidewalk and couldn't move or do anything and their needs went into the toilet and they got really mad. I've only had that happen once, though.