strange request here. at FOH I want to be the main iPad and on stage the remote, however I want the remote iPad to be the one in control of the songs. In other words the iPad at FOH is the unit multitracking direct into the desk to allow the multichannels (not possible via the usb on the stage iPad), but the song selection is made but he artist on stage. the reason I have this is that I have the opportunity to run multitrack files at FOH for all the singers songs lists, but don't want to restrict the singer to set play lists, but give them the freedom to chop and change as the dance floor dictates. the problem Is, that a simple TRS from stage to the desk won't cut it for multitrack, and to run USB from the Singers iPad to foh over 50 Mts plus is not possible. I would like the singer on stage to be able to select from the list of full songs available, which in turn triggers the iPad/MacBook at foh position to play the multitrack files into the desk, but the lyrics be available on stage etc. I know it sounds wiered, but I want the singer dictating the songs being played on stage to control the actual audio source at FOH so I can control the individual tracks to suit the venue