Yeah I think the ambiguity isnt such a huge deal. Even if you dont go the (in hindsight) logical way of leaving the eastern zone to the other sub to patrol, you will get the radar contacts from the nimrod to help your search after finding the friendly sub.

I liked the idea of having to try and ...

Sorry to Necro this thread but I saw the Author is still active here so I thought I would give it a try:

Maybe it would be worth tightening the ROE on the nukes for the Nato side a bit. I ran into an issue after stumbling into the friendly UK sub where it seems the NATO and player now get awareness ...