[wampwampwhat]

any of the Breville machines will allow you to use pre-ground beans. They're all 'semi-auto' machines, where you fill the portafilter with grounds and then install it into the group head for extraction. Automatic machines like the Delonghis or Juras you see in a lot of small offices don't allow for precise control over the grind fineness or volume. Though, I wouldn't recommend anyone use pre-ground beans if they're getting into espresso. The off-gassing accelerates exponentially as soon as the whole bean is crushed, and within 30 minutes or so of grinding many of the subtle aromatics and flavors that make good coffee 'good' have disappeared.