[Zope] Setting a session's domain

[Pablo Ziliani]

Hi all,
I'm developing a site that has multiple subdomains (i.e.: 
http://atlanta.website.com, http://nyc.website.com, etc.). Can anybody 
point me how can I get the session to be shared across these different 
subdomains? Unless someone can give me an opposite advise, I think I 
need to specify a "domain" to the cookie which is trivial for regular 
cookies but I just can't find how to do it with sessions (notice that I 
am I'm using Zope's regular request.SESSION).

Thanks in advance,
Pablo