We are in the process of remodeling our bathroom built in 1996 (florida). We have purchased a stand alone vanity with 2 sinks. There is a vertical opening from the top to bottom backside of the vanity in the center of each sink and a square opening at the bottom of each side, directly under each sink. What is the best way to deal with this and not violate any codes or create any plumbing problems (like back ups between sinks or water pressure)?

If you have a douyble kitchen sink take a look under the sink. Both drains can be joined in the same manner as the kitchen.

If you have a 2" drain already in place, this is how I would run it.

Note that the fitting is a Partition Cross and not a double san-tee.