qmail groups

Hello,

I like to use the qmail-group feature for generating a mailinglist like 
feature where I send a mail to [email protected] and the mail is 
delivered to [email protected] and [email protected].
I guess this can be done via qmail-group and an qmailgroup object in my 
LDAP.
My Question:
Why must I define a mailmessagestore an why do I need one if the mail 
should not be delieverd to a the group-user but to the groupmembers?
qmail-send checks if the maildir in mailmessagestore exists and also 
checks the correct permissions.
Therefore I have to make a maildir with the appropriate permissions for 
every gmailgroup I configure. This seems to be a time consuming work I 
like to avoid.

Or do I miss something in the config an general use of the qmail-group 
feature?

Greetings!

Tobias