@digipl, are you suggesting a remote service type of model? The two apps are independent and one provides services to the other. Interesting.
So, just to think out loud…
A service app may have little to no user front-end, just a messaging API. Although, I guess there may be value for a user to interact at the service level (e.g. having a shopping cart app show you everything you’ve purchased everywhere. Or a struggling husband blocks his wife’s shopping cart privileges… Hah!).
If messaging is to an MPID, then such an app could be running anywhere on the network. Any running instance could/would handle the request, which means some kind of “customer” or “cart” identification (app+user should do it, I think). Is it possible that multiple instances could answer these requests?
The user app would have to indicate somehow to the app launcher any service apps it intends to use, which would then have to either locate them on the network already running or launch them locally to handle requests.
How would “locate them on the network” work? How would you make sure that a remote instance stays running long enough for your use? Maybe we just always launch locally.
EDIT: I realized I may be misunderstanding MPIDs. When I launch any app, any MPID it creates is probably instance-specific (like a socket endpoint), not shared among all running instances. If so, then my above thoughts/questions about multiple instances and locating apps on the network are moot.