Connect Two New Sinks To Drain Line for Original Sink?
I have a double-bowl kitchen sink that lives under a pair of windows. The windows are separated by a 5'' molding. I am not sure if the drain is vented via a line up through the wall behind the molding, or if the vent line goes to the side of the window pair, where a plumbing stack lives (the drain for the second-floor bathroom toilet lives there, I'm not sure what else) There is no AAV in sight.
I plan to change this to two single sinks, about 34'' apart, flanking the location of the original sink and the original drain line and supply lines. Both sinks will have disposals.
Is it acceptable to plumb both single sinks to the original drain line using slightly sloped runs to a wye at the original drain line? And to supply both faucets from the original supply valves in the wall, using tees? Or, is it better practice (or required) to open the wall and run new, separate drain, vent, and supply lines?
The house is conventional wood-frame construction with an unfinished basement so there is good underside access for the re-plumbing. But running new vent lines would be a pain. I'd like to minimize cost if I can. I live in Portland OR.
Thanks for any thoughts.