It does seem that things are working out with your folks. Lets just hope if they happen to own their home instead of renting or leasing you do not get busted because if a charge of growth for distribution could be made to stick the authorities could confiscate your parents home/property. Well that depends on where in the world you live, but it can happen, it has happened, it does happen and it will happen again.
If you are in veg, which I believe from what little I have read you are, and you wanted to separate your plants there would be two options, but one is fairly risky and the other slightly risky.
You can cut your root ball in half and then cut back your plants to try to keep as equal of a balance between below ground growth and above ground growth. If you pull it off your plants will seem to sit and do nothing a bit but then they will take off like a jackrabbit with a roman candle stuck up its butt. If you do not get lucky, they will die.
The less risky way, but one that can be a pain but can also save plants that have to be separated, is to do a bare root transplant. You pop the plants/soil/root ball from the pot, rinse all the dirt off with a hose and then carefully separate the roots like freshly washed tangled long hair or a 'bird's nest' on a fishing reel after a failed cast, and then repot each plant spreading out the roots in the new soil as evenly as you can when planting. If done well your plants will never know they were moved.