My fiance and I are going to be under a family plan with the new iPhone 4S. He is transferring his number from T-Mobile and I will be receiving a new cell phone number. His contract doesn't end with T-Mobile until 10/26/11 so he won't transfer his number until then. Is there a way that I can activate my phone under the family plan I selected and when 10/26 comes activate his or do I have to activate both phones at the same time?