I've devised an alternative solution:
1- Create Assignment Buttons (shortcuts) that map inputs to a DynamicX output (X ranges from 1 to 4, which corresponds to four virtual outputs that can function as inputs)
=> Function: SetDynamicInputX.

2- Set up the corresponding activators for these inputs within the DynamicX output. Each button should have two activators:
=> Activator 1-Event: Default the color in a non-event state;
=> Activator 2-Event: InputDynamicX selects the color when the input is directed to the DynamicX output.


3- Finally, configure a button to assign DynamicX to the multiview layer.
=>
Function : SetMultiViewOverlay
Input: MultiviewInput
Value : MultiviewLayer, dynamicX

The drawback: The button selected may not truly represent the input shown in the Multiview. It actually corresponds to the button controlling the DynamicX output, and until this output is assigned to the Multiview, the intended correlation is not established. Consequently, the assignment button essentially serves to validate the selection within the Multiview layer.