How to send private message to multiple recipients

[picamajstori]

If you want to link someone to send a private message to a specified user (user id ###), you get them to click on following link:

www.forum.com/private.php?do=newpm&u=### (as a generic example)

And it will direct them to a PM page with user ### in the Recipient box.

However i am wondering what you would change the link to if you want it to create a Private Message with more than one user as a recipient. Ive tried things like &u=###u=$$$ and &u=###=$$$ and &u=###,$$$ but to no avail.

Thanks