Historically, the problem of same rank was simply solved by "date-of-rank." For example, see the controversy of Joe Johnston's and R. E. Lee's rank in the Confederacy. Would/could it work in the game?There is an issue with the split command that we have not solved. The command is in the game and does work, but the issue is still there.
I will illustrate the problem with infantry, since the terms are more known. If you are a brigade commander in charge of several regiments and you want to split some of these into their own unit, you have a problem. Say you split off 2 reg's and they get placed under a new brig comm, they are lost to you. You can no longer control them because the new brig comm is the same rank as you and you can only control units that are further down in the chain of command than yourself. So by splitting your strength, you actually lose those reg's. If you are a div comm, it's no problem, but at brig comm, there are many solutions, but no good ones that fit into the current structure of the game.
J