Add desktop app to Teams Channel

I created a Team channel for each unit in my organisation and I've been able to add apps (websites) they use daily as tabs in the Team. 

My goal is to create a single workhub for every team, so they navigate only within teams to do their work.

I am unable to add desktop apps to the tab and that is a significant adoption requirement for teams, especially the back office. These desktop apps are also Microsoft apps, e.g. Navision.

Anyone had this issue or can help with ideas on how to go about it?