Answer: -If you look around you'll find sink traps with one or two spigots to attach the outlet hoses to. Alternatively you can get 90-deg bends with the spigots on one of the branches. I got mine at Homebase. These don't have any 'magic' to prevent siphonage. I think I've taken care of that by having a sharp fall from the spigots to the horizontal run. -If you are plumbing the waste for the sink in from scratch there are waste fittings which combine one or even two spigots for attaching the appliance waste hoses onto. There are also fittings which go betwen the sink waste and the trap whcih have a spigot for an appliance. The important thing is to make sure that the appliance hose goes right up to just under the worktop before descending to the waste connection. Many appliances come with a U bracket for the waste hose which can be fixed to a cupboard side or the wall to ensure exactly this.