Sending group mails from Python

[Max M]

I am writing a small web based groupware program, and is often in the 
situation where I want to send mails out to an add hoc created group of 
user.

Ie. calendar notifications, information subscriptions etc.

Sort of an "embedded" list server.

Writing a program that sends out mail in Python is trivial, but my 
worries are that the server will be bogged down if there is problems 
with the mail server.

Does anybody have a clue/pointer as to the best approach or most common 
pittfalls for this?

I considdered using mailman, but think that it is a bit overkill. 
Especially if I want to make distribution of my app simple.


regards Max M