How to run on-demand asynchronous tasks in Simulink?

I wonder how one could implement an on-demand computation task in Simulink that will keep running in the background until finished while not holding up the step-by-step propagation of the Simulink operation.

An example would be: a vehicle follows a path provided by a planner module. The planner module replans the future path in an on-demand manner when a new situation is detected. The vehicle KEEPS TRACKING the previous path without waiting for the replanning results. And the planner module in the meantime replans the path for the new situation, which will take a few seconds of time. Once the new path is calculated, it replaces the old path in Simulink. An illustration figure is shown below(source of figure)

Can this be done for example, by two individual Simulink models, in which model A is running the vehicle controller with an existing planned path, and model B is the on-demand re-planner?

Any hint is appreciated.

[Tong Zhao]

Update: is it possible to use some Simulink-constructed communication protocol to link one Simulink model running on computer A to another Simulink model running on computer B on the same local network, and effectively creating an asynchronous communication channel in this way? If so, then I can place my main path tracking controller in computer A, while placing my on-demand planner in computer B.