Directors user sessions

[duja at torlen.net]

Hi,

I got a question regarding the Directors in varnish vcl. 
If user A is logging in to http://mywebsite.com and the website is using varnish (with directors) in front of 4 backend servers. 
The 4 backend servers is identical.

User A is logging in and hits server 1. He then goes to his profile and hits server 2. The server 2 doesn't know that user A is logged
and redirect him to some "Not logged in"-page.

Is there any way for varnish to lookup which server that user A should be directed to? Some kind of Sticky Session function?

/ Erik