Siblings Day was undoubtedly invented by Hallmark!! But there is nothing wrong with acknowledging a group of people who help define who you are!! I love having 5 sisters - not sure I always did - not sure I ever thought much about it - it was just the way things were!
Same goes for having 6 brothers - it's just the way it was!! Since I was one of the older siblings, some of my younger brothers feel more like nephews - but I'm glad they are willing to stay connected.
Happy day to all of you - you know, "the Clayton kids!!"