It is simple run multiple instances of HRD and switch between them
Surely you jest?
? Multiple instances of a program to interface to multiple ports? Are we talking DOS here?! Even DX Lab Suite will interface up to 4 rigs at once in ONE instance of COMMANDER interface.
Sometimes apps are quirky about where they store temporary files and multiple instances can cross-corrupt each other. It would be nice if you could either run it as a fully integrated platform with multiple radios working in concert but it may require a significant change in the app to make that happen. When it does work out that way with any app I have it is a pleasant surprise.