[LAU] Managing MIDI channels

Hello everyone! I've been doing home recording on my Ubuntu Studio for a while now but I've only recently delved into MIDI. I'm also playing keyboards for a band, and have just started to use LinuxSampler on stage, so I can play the very nice "Maestro Concert Grand v2" SoundFont. The problem: I need to switch between LinuxSampler and a couple of programs from my hardware synthesizer (which is the keyboard I'm playing) while playing, sometimes during a song. The connections are as follows: The keyboard/synthesizer connects via MIDI to my laptop running LinuxSampler and the Concert Grand. The keyboard/synthesizer is also connected via audio (two 1/4 inch jacks for stereo) to a USB audio Interface on my laptop. That interface then outputs a stereo signal (again, two 1/4 inch jacks) to the mixing console and the PA system. What I'd like to do is have the Concert Grand on LinuxSampler be "channel 1" and, say, the "Rhodes" program on my synthesizer be "channel 2". Then I would just change the output channel of the keyboard when I want to change between the two. Is there any way to manage the MIDI channels this way? I've tried a couple of MIDI managing tools (forgetting the names right now...) but haven gotten it to work. I hope I explained it well enough, it seems pretty complicated in my head... ;) Cheers and thanks for any advice! Kevin