With an assist for my memory and forgetfulness from Torsten I think i figured a way to do this. Firstly, my apologies for not getting the sync question right. Your setup worked fine except the switching between the 2 media players but you didn’t want then to play at the same time. That said I found a way to achieve what you describe. Here is the routing view
You can’t get the sync without the musical mode choice so both the players are set that way and both play and stop when the initial Main Transport is used as well as sync to the metronome. To get them to play separately I have set up 2 states and will be enabling or disabling the MIDI out route on each depending on the state. The first state is selected here and the first media player is un-muted. The other state “2” simply switches that to the opposite with the 1st media player route muted and the second enabled.
Here are the bindings
Notice that I use your original bindings and add the state switching bindings for the media players.
Also uncheck Tempo on metronome behavior.
I tested it here and it works! Sorry again for any confusion …