Option similar to RunVirtual key in App-V is helpful in launching applications like Office add-ins.
Thom_Cole While this doesn't cover all the cases that you likely want, in my branch of the PSF (TimMangan/MSIX-PackageSupportFramework: The Package Support Framework (PSF) is a kit for applying compatibility fixes to packaged desktop applications. (github.com) ) I have enabled you to include shortcuts to native exes in your MSIX package that will (with the help of PsfLauncher) allow those native exe processes to run inside of the container. This support is included in PsfTooling 5.2 and above and TMEditX 2.2 and above.
Keep in mind that the external program needs to be able to run inside a container also. So things like Notepad are great but don't even think about Office working that way!