Just as a counter message to the majority on here...
I'm yet to meet a family that splits things like this "equally" - and most of my friends/family who believe they are in a "fair" family, are actually the lazy ones who just think they are doing their share.
In reality, I would assert that for the vast majority of families, staying as a big group will always lead to an unfair distribution of the work. Someone will end up getting the rough end of it, and at best they can hope to be appreciated (but often not).
If you ask on here, you will get 95% of responses saying "Ditch them!, don't do it! Have it on your own!" but that is because people are responding logically, and not emotionally. Yes, logically you shouldn't be taken advantage of.
However, in real life, that doesn't always work. emotion, bonds, relationships get in the way, and it isn't quite so easy as "ditching them!". And even if you did, will that make you happy? It isn't so straightforward, and I don't blame the (large proportion) of people who taken on that burden in order to keep their family together and harmonious, even if it isn't fair.
For example, a mum taking on an unfair burden of hosting so that her family all get together, which means the grandmother can see all her kids and grandkids at Christmas. She isn't appreciated, but if she stops, they would all drift apart, the family would gradually split, and the grandma would loose the ability to see all of her Children/grandchildren together. Is it fair to put that burden on the mum? No. But it is. So the mum has to decide to do what is fair for herself, or what she can to make her family as happy/together as she can.
I'm not saying you should choose either choice, I just want to add a bit of balance to the pages of people saying "fuck them!!".