title: Varnish: cache only specific domain
body: <p>I have been Googling aggressively, but without luck.</p>
  
  <p>I'm using Varnish with great results, but I would like to host multiple websites on a single server (Apache), without Varnish caching all of them.</p>
  
  <p>Can I specify what websites by URL to cache?</p>
  
  <p>Thanks</p>