you can have 2 sims at same active career?

I've only had two work together by accident or maybe a bug (I'd like it to happen by design though). Basically I had a mother and daughter both doctors, with the mother further in the career (her daughter was a teen when she started) and when I went to work with the daughter on her mother's day off the mother appeared as an assistant so I was able to control her and since she had all her GP level interactions I actually had two people working for a change (The assistant's role remained unfilled and I didn't seem to be able to direct mother to work at the desk anyway when I checked out of curiosity).

The second time mother was called to be an assistant was for about two hours before her shift started, just long enough to repair an x-ray machine and admit a patient before she went to the sidewalk to 'go to work' herself. She stood there for a while before vanishing though.

I really wanted to be able to have control of both of them at the hospital when they were scheduled on at the same time and have control of multiple actives in any career at the same time as well so I wish this were possible on purpose.