hmmm now this is a good question, i have to admit that you will have to ask JCL regarding this topic.

I've read the "Starting the Engine" chapter in the manual. And it seems to me that starting the engine multiple times is possible but not from the same instance of an exe file. Engine_open() returns a pointer to a Engine_var struct, that's right, but there is no way (afaik) to tell the engine if a certain command like ent_create should be executed on Engine_ref1 or Engine_ref2.

What may be possible in your case is that your program creates one instance of the engine (like normal) and then it executes an exe file that also opens the engine (thus you would have two instances of your program). And then you could communicate between them with multiplayer commands (as stated in the manual). And thus it may be possible to embed the other instance into your main programm by passing the hwnd pointer - or something like this ^^