You probably could...
   Pretend you wanted cg-news from cgtalk
    1. put cg-news URL in project Web-Addresses
         <http://www.cgtalk.com/forumdisplay.php?f=59>
    2. Option>>Scan Rule filter out non threads/forums
          -* 
          +www.cgtalk.com/showthread.php?t=* 
          +www.cgtalk.com/forumdisplay.php?f=59*
    3. Option>>Limit>>Mirror Depth = 2 (internal) 
         (external=0 No links outside cgtalk doamin) 

Try on smaller categories first to make sure it works
  For very large forums remember <20k files/directory
   (so split up jobs/alter build  appropriately)