Sending Two Or More Data Streams With gnuradio-companion

This video shows an example of sending two data streams with gnuradio-companion. The "sendTwoGnuradio.grc" file sends two wav files on two different frequencies at the same time. The example grc file can be found at -
github.com/righthalfplane/rfs...
Here is a simple C++ program that does the same thing -
github.com/righthalfplane/rfs...