As a fellow MMORPG player, I've to use Ventrilo much for dungeons and raids. It is really borning if you are the only one person in vent. So, I tried setting up Music Bot (you can also call as Vent DJ) on macbook.
First, you will need to install Soundflower. You may ask what is Soundflower for? This application is to route audio between applications, without using physical cables.
Signed Version for Yosemite/Mavericks/El Capitan
For audio player, I use VLC Player to play music (since iTunes is hard to switch audio output). You can easily change your VLC player's audio output from navigation menu. (Look image below)
Go to Application folder and clone your Ventrilo app; select app and then Command+C and Command+V. (Rename it to anything if you want to). The reason of copying into two app is to allow you to use another ventrilo app to login and chat with your friends also.
Open Your Ventrilo app you want to set up music bot. And then open Setup. Change sound input to Soundflower (2ch) and also make sure to uncheck Use Push-To-Talk Hotkey (PTT Mode).
Click OK and you can start using your Ventrilo music bot!