Mann Vs Machine with friends

Hello, for a while now I've been wanting to play Mann vs Machine (Mann up mode) with friends. But since this is my first time playing MVM, I was wondering if my friends have to have their own tickets to play. To make it easier to understand, if I have 4 tickets to complete a tour, but I want to play with my friends, do they also have to have the 4 tickets to be able to play? Excuse the poor wording or if it was not understood, thank you very much in advance.