I think one aspect of being IFB that needs to be clear is whether or not the persons allow scripture to change their lives. I know that even amongst IFB there is disagreement on things like pants on women, some music styles, etc. That isn't what I'm talking about. I'm talking about the tendency of some posters to post things that are phrased as a question or an honest search for truth, but then turn it to their actual intent: to push their wrong doctrine or to snipe and pick and sneer (however politely) at IFB for wanting to stand on truth. How that could translate is the problem, but I think Pastorj has the right idea.
Rather than limiting IFB forums to a certain section, why not limit non-IFB to certain sections and have the main parts of the forum for only IFB. Like the Lounge, as Pastorj suggested. Perhaps the Lounge and Current Events, since the two would likely cross at times.