Yes, for VST plugins you can set your external device to a port in the MIDI settings window and then use that same port value as the input port in the wrapper settings window of the VST plugin/s that you want to use.
Then when you change the MIDI channel on the device, it will play on that channel in the plugin (if the plugin supports multiple MIDI channels of course).
This doesn't work with most native FL plugins, however, since they don't have a port selector and generally they're single-channel.
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