Channel conflict? What channel conflict? That's the story according to a new ``E-tail Economic Study'' from McKinsey & Co. and Salomon Smith Barney, which urge e-tailers to sell across multiple channels--store, catalog and online--in order to beef up their margins and survive the dot-com shakeout. B-to-b issues, such as how to deal with conflicts between multiple sales channels, were supposed to fade away as the Internet enabled perfectly efficient direct e-commerce. But as online sales have proved a money pit, McKinsey and Salomon say e-tailers must go multichannel, drive up average order size, hold the line on discounting and concentrate on higher-margin products in order to survive.