& @lock indirect
 
  INDIRECT LOCKS:
 
  Key: @<object>

  You may reference the lock on another object and use the result of
  evaluating that other object's lock.    You pass an indirect lock if 
  you pass the default lock on <object>.  This is especially useful 
  if you have a large number of objects or exits that want to have 
  the same lock, and you want to be able to update one object and 
  have all the other locks change at the same time.
 
  <object> is searched for when you enter the @lock command and its
  database number is stored in the lock, so something like
  '@Lock north=@master.lock' is safe even if you are going to move 
  master.lock to another location.
 
  Examples:
    > @lock master.lock = me
    > @lock north = @master.lock
    > @lock south = @master.lock
    North and south all reference the lock on master.lock, so you may 
    change the lock on all three exits by changing master.lock.
  See also: @lock normal.