@FlexMundo says it here:
The key is using the Overbridge plug-in for each of your Elektron devices. Drag and drop whichever box (DT, DN, ST, etc) OB VST onto a track, and it opens up the ability to select individual tracks out from it, without having to set the box as your interface.
Whenever I am using soft synths in Ableton, I sequence them from my DT. I just prefer the Elektron sequencer to drawing notes in a DAW. Plus I can easily PLock MIDI parameters as well. I don’t really set up individual MIDI tracks (unless I want to record the MIDI information separately), but just set the MIDI source to be my DT.
You should be able to record the main outs of your ST as a stereo track…this will be the entire mix from your ST. You should definitely be aware that recording individual tracks through OB for any of the Digi boxes means that they are captured dry, without any effects on them. All of the effects are send effects, so they are processed all at once for every track that is using them. One thing you can do if you want individual track but also the effects (also if the ST works like the DT, which I am guessing it does) is mute each track individually in SETTINGS->AUDIO ROUTING->ROUTE TO MAIN page. Then so long as you set each individual track up through OB and also use the MAIN outs through OB as a stereo track, you’ll have the dry signal of each of the tracks isolated, and the effects from all of the tracks isolated and summed in the MAIN out.