Please excuse newbie ignorance as far as terminology, etc goes... Currently my washing machine discharges into a stand waste which exits the external wall separately to the kitchen sink waste. I am about to add a dishwasher, and replace sink and will be re-plumbing all the wastes. I would like to combine the three wastes somehow so that there is just one waste pipe emerging outside, low on the wall just before entering the gulley. Can I add a stand waste for the D/W then join this and the W/M waste into the sink waste just before it exits the house (using T-junctions, or a manifold - if such a think exists)? Thanks