My (28m) gf (27f) is meeting my entire family do i need to formally introduce each one?

My girlfriend has already met immediate family (Dad, Step-mom, sisters) but the entire family is going out for dinner and its a total of 31 people. Do I need to formally introduce her to everyone or is a simple "Hey this is my girlfriend _____"

Usually I try to introduce little by little, but in this case I thought it was be easier to just let her meet everyone.