Yikes, what an awful experience! I can sympathize very much with what must have seemed like an impossible situation, especially since I had a "drinking dream" recently that was eerily similar.
In the dream, just as you were in real life, I was in a situation where refusing to drink would have been a terrible social faux pas and created a huge amount of discomfort for a large number of people. In my dream, I took the drink, justifying it by telling myself that the needs of the many outweighed my own selfish needs. I awoke with the usual feeling of shame and hangover-like symptoms that many report having after drinking dreams.
I hope never to be faced with such a terrible dilemma in real life, but if I am, I hope I will be able to apply the principles I've learned in recovery and remember that other peoples' feelings are not my responsibility. My own selfish need for unbroken sobriety does indeed supersede any social obligation to spare the feelings of others, or to save face, or to avoid having others think ill of me.
The only possible exception I can think of is where my refusing to drink a toast would actually endanger others, like if I were a diplomat at a reception with a backward country where refusing to drink would be taken as an insult and threaten relations between countries. Thank goodness such a situation is unlikely to occur in real life!
If this had happened to me, I would think it important for me to examine carefully my intent, acknowledge where I went astray, get back on the horse, and soldier on.