Several agents determination

[ezra]

Hello all,
I have two questions:
1. I've heard there is an option of defining a role in such a way that the agent is determined by a function module,
    How do I do that ? and what interface does the FM must have ?
2. I am trying to send a WI to an entire org. unit ( I meen, to all users under this org. unit ),
    Is it possible to do so with the FM mentioned above ? if not, how can it be done ?
 
 
thank you,
Ezra,
 
By the way,  Is there a site with refferrences to examples of implemeneted WFs ? or any other implemantation tips ?