Bringing an unlocked phone to a family plan

I was looking at the Oneplus One phone and it looks amazing, but I've never used an unlocked phone before. It seems like it usually is a straightforward process for individuals, but I am not an individual nor am I the person making the decisions or payments for the plan: I'm on my family plan. 

Am I still able to be a part of this existing family plan if for my next phone I bring my own unlocked phone? Or would I have to make a new plan for myself?

Thanks