Creating new posterous site

[gabusingh]

hi,
I am running a wordpress website,
I want to give my users/contributors a new posteorus site account &
email to post into that,

my primary domain is in wordpress.org and self hosted,

Primary Domain : domain.com {WordPress}
Author sub-Domain : username.domain.com {posteorus}

I will use custom domain settings for those sites,

So whenever anyone signed up into domain.com{WP} , I want to create a
new blog at posterous and with url username.domain.com or
username.posteorus.com atleast.


Is that possible. Plz share your idea on it.