Friends' Squad loses player to other team

I create a Squad in the lobby, and my four friends join. Then we all get into the same map and create a new quad there, like Golf, for example. We even make it private. But then, half way through the game, one of us will invariably be bumped to the other team. It really ruins it for all of us because we're all on Discord and now we can't really talk openly because one of us is "the enemy." It's even more unpleasant for the person who got bumped because now he can no longer play with us as a covert team. This is super frustrating and is ruining our experience. We came to BF4 from BF1 because we wanted Hardcore mode. But now we're encountering this constantly, virtually every server we play on. Please advise what to do. Another odd thing is that as soon as one of us is bumped to the other team, it's like the server back-fills the team he was on. It seems logical to me that the server should keep Squads together if at all possible and move individuals if, for example, it has to re-balance. All of our skill levels are just below half on most maps, so it's not like we're really good or really bad, i.e. one or the other extreme. I sure hope someone can provide a solution, other than giving up on this game.