My kinda complicated but working solution to use the App together with others in the Tabletop Simulator:
-Install MoM with Steam on another Machine (in my case a laptop) with another account or in Offline Mode.
-Start a Meeting on the "MoM Machine" with https://www.join.me/
, a simple free meeting tool that allows to share control with multiple users AND the meetings can be joined with a invitation link from within a webbrowser, even from the Steam Browser or the TTS In-Game Tablet.
-Start the TTS Session on your main machine
-Spawn a tablet an open the meeting invitation link
-Everyone who joins can now see the Display of your "MoM Machine" the In-Game Tablet
-On the "MoM Machine" you can grant control to whoever wants/needs to control the app.
-If you want to send the App Sound to the other players too, you can set up "Stereo Mix" as your recording device, and use Skype or Teamspeak to stream the sound to the other players. Be sure to mute any sound except the App sound to have no noise or feedback from the others