Here the way I do it.
Create model #2 and give it a non-conflicting start channel. Note what the Universe / Channel will be in xLights.
Set the controller output to use that same Universe/Start channel on the output you'll use for that model.
If xLights says absolute channel 5192 is Universe 14, channel 6, then set output #13 to start on Universe 14, channel #6.
I know there are other ways to do it, but that's the way I do it.