Two Norfolk pinned
What do I do when two Norfolk lines are growing in the same pot
It's possible that these are the same plant.
These plants are grown from seed or cuttings by nursery industry professionals and even if they aren't the same plant, they are probably pretty intertwined.
That said, you could try re-potting in spring, and if they are able to be eased apart without much difficulty, plant them separately.
You would use a soil-based potting mixture, and 5-inch pots are usually the largest you will need. (Large, mature ones may eventually get to 6-8" pots)