Technically, the answer to your first question is certainly "yes," but I assume what you are really asking about is whether there would be any 410(b) coverage or other qualification issues/roadblocks to address. Someone needs to determine if the Schedule C trade or business is a member of either a 414(c) group or a 414(m) group with the medical practice partnership (or any other trade or business with employees). If not, there shouldn't be any issues with setting up a separate plan just for the doctor's Schedule C business.