'm trying to migrate to tmux from gnu-screen. There is one feature in screen that I can't figure out how to do in tmux. Specifically, with screen I have one window and I can split that into multiple panes and, most importantly, I can have more pseudoterminals than panes. For example, I'll often have two panes but will frequently swap between three different terminals.
In tmux, I seem to always have just as many pseudoterminals as I do panes. What set up and commands will give me the behavior I like in screen in tmux?