Playback file on multiple frequencies

Hi everyone.

I have a single channel radio (USRP N210) that I am trying to playback a
file on multiple frequencies with. I assume a need a sort of
channelizer function but am having difficulty implementing this.
Basically, I have a WAV file that I need to playback on various
frequencies that I set and have it combine into one data stream for the
N210. Can anyone advise on ways to do this?

Thanks,
Tim