Sending from multiple Mailgun domains using Laravel Mail facade

I'm using the Laravel 4's Mail::queue() to send emails, using the built in Mailgun driver. The problem is that there are multiple Mailgun domains I would like to be able to send emails from, but the domain must be set in app/config/services.php. Since I'm using Mail::queue(), I can't see how to dynamically set that configuration variable.

Is there any way to do what I'm asking? Ideally, I'd like to be able to pass in the domain when I call Mail::queue() (the Mailgun api key is the same for all the domains I want to send from).