Send a message to a specific adapter

[josegonzalez]

What I'd like to do is create a slack/irc bridge. It would be great if we could have access to a specific network connection, such that I could get a message from one network and post it to the other (and vice-versa).

Do you have any thoughts on how I might make a pull request to add that functionality?

[bnfinet]

I wonder if any of the messagestreams cross protocol delivery in cmd.go could be modified to serve the same purpose.