Are TG orders, production orders, etc. saved even if you don't advance time? If so, I could see a situation where two players shared the Aurora folder in an equally accessible database somewhere and advanced time when agreed upon and both teams have had a chance to create orders as a slight improvement over PBM, although it would probably get very cumbersome to say the least.
Probably best if your opponent is available for hot seat gaming if you get into a shooting war.