Why didn't Alia Bhat and Ranbir Kapoor's family celebrate Christmas together?

Not just Christmas I did not see Ranbir Kapoor and Alia Bhatt's family celebrate a lot of festivals together with each other. They always invite the couple to celebrate with each family separately. Is there any particular reason behind it? Maybe they so spend time together but not so much as there have not been many photos of them together but just separately with Alia and Ranbir