Mix Mic and application sounds out to another app

Goal - I teach in a live online classroom platform called Collaborate (used to be Elluminate). I want to be able to have my mic (my voice) mix into a single input channel with output from an application to the online classroom. With the students being there live, recording apps are not needed, merely a live-time sound mixing tool.

Examples of use: While I am talking on the mic to be able to blend in sound effects from a sound effects cart. Another example of use is to pipe in the sound from the application in application sharing mixed with me talking on the mic. That is not currently possible from within Collaborate other than to toggle between inputs without actually mixing the sound sources together at the same time.

Details:
Collaborate does let you select input and output.
Some of the applications that I want to mix my mic input with have selectable input and output and others do not. They merely send out to the system default device.

Thanks for reading. :0)

Well, in my continued search, I have found part of the answer I needed. Any application that I can set an output for I can get to mix with my mic in Collaborate by using a combination of SoundFlower (free) and LadioCast (free). I just set my app that I want to mix with my mic to Soundflower's ch2, then in LadioCast I set the input (you can have up to three) to my mic and also SoundFlower2. In LadioCast output, I set it to SoundFlower's ch16. Then in Collaborate I se it to input for ch16. Viola, I can talk on my mic and at the same time the app sounds mix in for the students to hear. Oh, in the Soundflower that runs in the menu, set it to your headphones or speaker settings to have a monitor so that you can hear the app too.

Now, the last thing to figure out is how to get sounds from apps that you cannot specifically set the output for such as iTunes. These I suppose just go to the default output. I need that default output to somehow get rerouted back in as a selectable input in LadioCast. On a PC, I could just use mono or stereo mix. Mac doesn't seem to have this option. I have downloaded Linein which should act like a virtual patch cord, but not of the settings I tried worked to get an app in to LadioCast. Anyone know hat I am missing or know of a better way for non-output controllable apps?

Nice work, and thank you very much for following up. I'm sure it will help someone in the future.