Is there a way to invalidate a cached item on multiple varnish servers at once?

[James Pearson]

Excerpts from Rainer Duffner's message of 2013-09-29 13:45:51 -0700:
> Hi,
> 
> suppose you've got a couple of load-balanced varnish-servers, is there a way to have an item removed from the cache on multiple servers at the same time?

How small of a window do you need?  I'd probably just fire off a PURGE request
to each server, but that'd give a few seconds where some servers would have a
cache entry and others would not.
 - P