This Saturday night we are hosting our annual Winter Solstice party. We have it every year and we always make sure to go all out with awesome catered food and booze. We typically have a decent number of people attend each year which are friends from college and our co-mingled group. We had a friend-couple (a couple we are friends with) that we invited for this year ask us if we would "mind" if they had a "surprise wedding" during our party. I was shocked because...who wouldn't be! We've been friends for years and we love them dearly but it's kind of our party that we our money into and we do celebrations to celebrate the season/coming new year. It just seems like they are trying to take over (want to invite their parents and a Christian pastor).
Help on what to say/do with this?