Soil pipe one way or the other

[MikePF]

I've installed a Vortex sewage treatment tank alongside the existing septic tank but, instead of switching the drainage over permanently, I was wondering whether there was any kit which would allow the waste to go one way or the other in future. The idea was that, if anything should go wrong with the Vortex operation, there would be a back-up. I've fitted a distribution chamber (with compression-adjusted blanking plugs) as a temporary measure during the installation process and it works after a fashion but of course it's not designed for use upstream of a treatment unit. Does anyone know of an approved system?