[Zope] groupware (like yahoo groups) for zope / plone?

[Tariq Rashid]

hi - i have been searching the websites and google and the zope/plone
product pages for a "product" which will work like a groupware/colloration
system - much like Yahoo Groups. 

features desired include:
	* email and list messaging
	* filestore for multi-type documents (eg pdfs)
	* shared calandars / meeting

i have pnly recently beocme familiar with zope and plone and have a site up
and running but which is "presentation only" for the pubnlic - a groupware
system would be much more interactive ... 

i know i can install things like PloneMail or similar ... but i don't know /
want to program the underlying mechanisms to propagte meeting invites etc
etc ... 

the CPS website is not very open - i can't see a list of features or
screenshots or a demo site. 

does anyone know if something like this exists?

i am keen on a zope/plone solution because it would keep things simple and
reduce the dependence on multiple platforms... i want to stick with an
OS-independent zope/plone .. benefit from the zope scalable middleware and
have simply replication/backup options that zope/plone gives me (data.fs?)

thanks

tariq