Originally Posted by Vainamoinen
The scene in which Jess asks about Sarah is a hint for the sake of a hint. If there was an official confirmation, this wouldn't be a hint any more.
In other words, TTG suggests this correlation in exactly the same way the Lost World movie did.
I have to point out that this is not discussed in the film, but in the novel. In the films, the connection is not made: in the films' universe, there's no way of knowing if Gerry Harding and Sarah Harding are truly related, unless specified in a future installment. (Which seems doubtful.)