The Drifter Challenge - House 005 - Rules

Hi All, long time no see lol, I have not called in for a while, although still drifting of course. I just have a question with this one, do both sims have to reach top of both careers? or one sim each career, 'm hoping the latter cause I'm having a little trouble with this one lol heir just about to be born, one is lvl 7 other is lvl 6, I just find it's really slow to progress. I was up to house 5 before, but I restarted the whole challenge again cause I lost my story from my founder :( and all the photos, so being perfectionist as I am I couldn't survive without that lol, yeah, weird, I know. Anyhoo I had just assumed it was one sim for each career, but then a horrible thought popped into my head and I just had to check. Hope everyone is going well and having fun as always, have to catch up on people's stories, haven't been on for aaaaages.