Dear Mary: How to enlist people with field marshal experience to deal with bossy party hostesses

Q. A friend generously hosts an annual Christmas party in London where we see many old friends we have been missing since we moved to Dorset five years ago. However, for the past two years she has ‘taken over’ and will not allow any people who already know each other to chat. She barges into groups bellowing ‘This won’t do. Come and meet new people!’ It is irritating, to say the least, to be frogmarched off to various ends of the room to join equally bemused and irritated strangers. She does not let up for the duration of the evening, constantly breaking up groups, and berating those who won’t play ball. I am certain all the guests feel the same way as we do, and we are even considering refusing the invitation this year. Mary, how can we persuade this kind yet bossy hostess to let people enjoy themselves spontaneously without her intervention?
— P.B.,