how do IRC users write to Tox users?

So far it's looking like a one-way bridge: a tox user can join an irc channel and send messages to the channel, but it doesn't seem like the bot echoes all traffic on the channel back to the tox user?  also, the bot represents itself as just one user on IRC, but what if multiple tox users share the bot? how does an IRC user send a message specifically to one of those tox users?