Why, yes, yes you can...
The thing to do is build about a dozen or more missions, using cryptic file names that make absolutely no sense, then only put a half-dozen in the game at a time, so that you, as the author, might forget what they're like, and not have an advantage over your opponents...
When the little app opens, do File, New and type in the date you want for the mission. Then, on the Mission page, choose Parameters, and be sure and change the "Mission Type" near the top from "Single Player" to "Multi-Player", and then click on "Accept" at the bottom. There is also a choice for "Cooperative" and "Adversarial" up top. You can have up to 8 submarines in a cooperative mission. I cannot remember how the Adversarial works...
I cannot remember if RGG works in a MultiPlayer mission or not, and I can't test that right now, since my other computer with SH4 on it is down right now... If they do work, you can put a "RandStartRadius=0.000000" (which is in kilometers) of up to 100 - if I'm remembering correctly... maybe 20... Just make sure that any RGG you create isn't anywhere near a land mass that would fall within that range, and that any sub you add to the game is farther away than 30km, which is the spawn "limit". If any player boat is within that limit, the RGG won't spawn. For testing purposes, you could set "ReportPosMin=-1" to a positive number, and then the game will generate one of those messages like "Enemy convoy reported Longitude / Latitude, course and speed"... If RGG won't work, I am sorry for chasing you down that rabbit hole ahead of time...
