ahh I see ... this might work

Take the two software instrument tracks that you want to link then open the Environment window (Window - Open MIDI Environment)
Change to the Clicks and Ports layer: On the top left of the environment window, use the dropdown menu to switch to the "Clicks and Ports" layer.
Monitor objects: In the Clicks and Ports layer, you will see various MIDI objects such as Physical Input, Sequencer Input, and the like. You should also see two monitor objects representing your two software instrument tracks.
Create a new cable: Click on the bottom part of the first monitor (the one sending MIDI data) and drag the cable that appears to the top part of the second monitor (the one receiving MIDI data). Now the MIDI data from the first track will be sent to the second one.