I've been to a number of wine friendly functions, receptions etc. where the wine was on the table prior to the arrival of the guests. At one particular party, four or five different red anf white wines were spread throughout the room in random fashion. This was cool, as the winos were able to mingle from table to table trying different wines. In this type of set up, no one thinks twice about the wedding party drinking different wine.
Another alternative is to have large format bottles on your table. If someone inquires about them, say it was a gift.