you probably could now. You can always pot the bigger ones singly and return the smaller to a 'shared flat'. If you've had it awhile and it's doing well in its current mix, I'd use the same or as close as you can manage. Otherwise, a little smaller and more moisture retentive than what you'd use for the older plants. I've separated the babies by gently swishing them in a bowl of water to help break up the clump, then teasing the individual plants out. I don't know if this is proper, but it's worked for me.