Split And Move (to same Dorm) Not Working

@LunarCynthionThe dorms are not like TS3 or TS2 all sims that join dorms are playable sims. All sims that join the dorm from the school window are playable sims, so you must play all playable sims in the dorm. If you want sims to go to school with your sim create a club and call it dormmates or whatever, than go into edit dorm and choose the club dormmates, they will than show up as roommates if they are old enough to qualify.

Edit 1: think I miss understood your question, I think there is a protection in place if there is kids or pets when you move the last member of your family into a dorm your have to sale your house, this game considers university a full move instead of a temporary move.  If you have objects in your family inventory the game won't allow last members of the family to move out  to dorm, as dorms do not have family inventories.

Edit 2:  In order for all family members to move out into the same dorms they must all be accepted into the same University.

Hi Sid, thanks for the quick reply.

Answering to your first edit, I did send away the kids of my sims to their teen siblings 😢 (They're gonna have a hard time handling high school, part time job and their little siblings RIP) and all the pets my Sims had, reached their expiry date 😢 There was no one except both the twin young adult Sims.

Answering to your second edit, both the Sims did get accepted into the same University or the option of moving in together shouldn't even exist. (I made sure my Sims were eligible for University by upping all their skills to 10 and receiving the acceptance letter)

Update : The Sims do move in together into a dorm but I have to restart the game for that because when I move in the 2nd Sim with the 1st Sim the game just kind of hangs/crashes (there is no way to know if crash or hang happens since there is no button to press to check)