The answer is simple. Do not bi-wire, problem solved.
I don't mean to be flip here, but it's the truth. While there remains a few stubborn holdouts in the audiophile world, for the most part, bi-wiring is generally acknowledged to be ineffective. Neither the legitimate science nor the countless blind listening testing supports there being any audible difference gained from the practice.
Sighted tests, yes, people can hear differences, but that method is rife with psycho-acoustical error, not to mention other confounding factors which interfere with making impartial listening judgments that would reveal the sobering truth about the inaudibility of bi-wiring in practice. Speaker manufacturers design to allow for bi-wiring only because there is still enough of a market for it, and after all, they are in the business of pleasing as many customers as possible, just as long as it doesn't significantly alter their design goals. Adding another set of posts does not.