How to send simulated operation of mouse movement to UE4 application

I am writing an simulation controller that needs to accept multiple inputs at the same time, each input corresponds to a different UE4 process (these processes are provided by the customer, I cannot modify them)

Customers send keyboard and mouse information to the controller through websocket, and the controller then controls the corresponding UE4 process through the system API. It is currently found that the process can be distinguished by PostMessage(window, xxx), and mouse click and keyboard input are all achievable, but the mouse movement (camera) does not work

I read the latest UE4 source code from github. There are two kinds of messages that control the mouse movement (WM_MOUSEMOVE / WM_INPUT), and if FReply::UseHighPrecisionMouseMovement() is called, WM_INPUT will be used and WM_MOUSEMOVE will be ignored

I looked up some relevant information from the Internet and tried to simulate the RAWINPUT message, but found that it could not work, because UE4 will fail when calling GetDeviceData () to parse the RAWINPUT, unless I can modify the WM_INPUT method of UE4 processing, but unfortunately, the UE4 application It was provided by the customer and I cannot modify it

Apart from “Pixel Streaming”, is there any other way to simulate mouse movements for specific processes? Thanks a lot!