It seems as if there is always someone who orders fish and someone who orders meat. If the table is large enough, you can always order a bottle of red and and a bottle of white. If it isn't, ask the people eating fish if they would be satisfied with red wine and, if so, order a lowtannin syrah or a merlot that will satisify the meat eater without offending the fish eater. Determine the current attention level of the diners. This may sound odd to you, but it's based on experience.
Diners are more attentive to the first wine than the last one.
Interest is focused and alert for a wine appertif, so this is generally when we order something unique or special a vigonier, Cotes du Rhone, syrah, for instance. Once the food arrives, we often shift to something with more weight. Food can offset tannins and acid. But if we need to order a second round of wine for the table and the focus is heavily on conversation, we actually downshift to a wine that is still good, but not as pricey. If you follow this strategy for the table, then your objective is simply to find the best wines on the list.