Populating associations

Hi all,

I have a Message class which has_many Message_Users, Message_User is basically a join table with an attribute, and belongs_to a User.

so it kinda looks like the following:

Message has_many :message_users

MessageUser belong_to :user

User - lots of user stuff

What I want to do, is on the Message create screen have a list box with all the users in it, and when the Message is created have it automagically create 1 MessageUser for each user selected, and link them to the new Message through the MessageUser association. Is this possible, or do I need to grab the list of users selected and manually create the structures?
Or can anyone see a better way to set up the structures?

Hope the question is clear.

You may want to check out this blog post. I think it may help with
what you are looking to do: