This problem is from far away, but launchbox team doesn´t solved the problem yet (I don´t know if they know about it)
Basically, if you use the additional app section, you can launch a program, a batch file, etc, before the game opens.
The problem here, is that, even if you use the "Wait for exit" option, the rom is launched after 15-20 seconds, it doesn´t wait for the user to close it. This is really annoying, because, for example, i launch .txt files with some instructions to read. And the rom doesn´t wait to close the window.