My grandma always hosted our family get togethers for our convoluted split-apart, remarried, and generally crazy family. She would do more of a pot-luck, so that she wouldn't be stuck spending her entire day preparing. She would do the main course, chips and dip (family tradition dip.) and some meat/fruit/veggie trays. Everyone else would bring a desert, salad, appetizer, whatever. If the kids don't eat, that is the parent's problem. lol. She was very strict that if you want to drink something you stay outside or in the kitchen. Anywhere else in her house, it's water only. Alcohol included. We would always invite girlfriens/boyfriends, whoever. We always saw it as a great way to introduce the family! It was never awkward for us, because we always had so much going on that they would be incorporated right in. We usually spend the time before dinner hanging out and catching up, just socializing. Dinner itself is always very informal, because my grandma's kitchen was nowhere NEAR big enough to seat everyone. Heck, it was barely big enough to set out all the food! Usually we would serve ourselves, the adults would find space on a table or in the living room with a TV tray, and the kids (and teens + younger adults) would find room on the floor. After dinner, the designated unluckys get to start the dishes (For YEARS it was my cousin and I, until the next generation was old enough) while everyone who felt like it would help clean up the rest of the kitchen. We used paper and plastic too, but the pots and pans always needed done. That way when we left my grandma wasn't stuck with a trashed house. Then some of us would play cards, some would watch TV, some would head outside to do whatever... after a little while we would eat dessert. Then we would hang out for a little while longer, and people would leave. Usually, most of the family left at once, and my cousin, my other cousin and her kids, and myself would stay and hang out longer.
The only holidays she does are Christmas and Thanksgiving. Usually the other holidays were a come if you want to, and we will have a barbecue type situations. lol.
I'm not sure how many people are involved in your situation, or if your family would consider it rude to help each other out (or expect the help) the way we worked it... but it worked (Heck, still works) well for us. :)