title: Interaction between multiple select boxes
body: <p>I am new to Angular.js and have a design question.</p>
  
  <p>I have three multi-select boxes on a page, one for Products, one for Users, and one for Groups.
  On page load, Products shows all Products, Users shows all Users, and Groups shows all Groups.
  When the user chooses one or more Products, Users and Groups should each refresh to show only those users/groups that have used the Product.</p>
  
  <p>What is the Angular way to design the interaction between these select boxes?</p>
  
  <p>My first approach is:</p>
  
  <ul>
  <li>Each select is fed from an $http.get() to fill it</li>
  <li>When user taps on a Product, listen to that select (with jQuery on()?), construct the $http.get() request, and update the models. This will update the select boxes for Users and Groups.</li>
  </ul>
  
  <p>This feels very... un-Angular. Suggestions on how to improve it?</p>