Hi Ryan, I admin a Vent server for my clan, so maybe I can help you out.
If I understand you correctly, you want to change a user's default channel, right?
This can be done either when creating a user account or via the User Editor afterwards.
While creating or editing the account, go to the Network tab. Down at the bottom, you'll see a box labeled "Default Channel"; if you click on the box next to the input field, it will give you a list of all the channels you have created in your server. Select the one that you want your user to go to when he enters the server and your good to go. My default channel is my work room, so I can bypass the lobby and get straight to whatever needs to be done.
Please note that each individual user can also set his or her default channel by going into clicking on "server" and manually typing in the name of the room he wants for a default channel, as long as the room is not password protected. If it is, he will have to be given rights to access that channel.