Each year at the sales in Jan and after the fourth of July I purchase shirts for our entire family. Girls get one color , boys get another the colors go together well for a photo. I buy all of the same (so no one gets hurt feelings.
At the Holidays in the summer and in the winter I gift these shirts (the summer ones are always in the birthday boxes) We take group photos (if a family can not travel I mail the shirts and ask for a photo for my gift)
This has worked so far. For Christmas this year the girls have blue the boys have grey.