Force users to select package before register.

Hi,

By default in PRO SITES when a user go to the register page it goes to a form, they create an account and a website for free and then after having the website ready they can upgrade to premium.

Is there a way to force the users to select one package before they register? Because in the home page I have information of different packages and the user gets confused because they can't select any packages at the beginning.

What options I have here?

Thanks!