In the movies they always act like vampires stick together, but this isn't true, a vampire can eat another vampire, a vampire to another vampire is still just a strong human, there is nothing differentiating them from food. Vampires have no friends, generally.
@Remejy I don't subscribe to that part of lore, vampires are, for me, symbolic of sadists or of users of other people, in real life they don't get together and joke and smile about all the people they've killed or hurt, they are just as much a danger to each other as to normal people.
The closest thing a vampire has to a friend is a slave.