If you want BandHelper to not send a MIDI program change when a song is selected, you can turn that off by going to Repertoire > Layouts > [layout name] > Edit Details > Actions and clearing Send MIDI. You can then send the MIDI a different way, either with a song second selection, or a two-fingered tap, or a foot switch, or just click the MIDI button on the screen. You cannot have it be conditional on whether the song was selected from an incoming MIDI message.