You didn't mention if you will all be together for the holidays or sending gifts. The important thing to make this work is to get everyone on the same page. If you are sending gifts, perhaps everyone can agree to something homemade or at least a specific price range. I worked somewhere with a "secret santa" grab bag. Everyone bought a gift for someone. The price range changed from year to year, but it was on average, maybe $20-25. By a certain date, everyone was required to make a list of some things they might like that could be purchased in that price range. It was still fun b/c you didn't know who was buying your gift or which item they might get for you. The person might get creative with the gift wrap or if they had some $ leftover, pick out a little treat you weren't expecting at all.
Last year, on my husband's side, my sister-in-law & I agreed that we would just buy for the kids. That was a lot less stress & a lot more fun for us. I did give everyone Christmas photos (8 x 10 taken & purchased at Picture People, scanned by me on my computer, and additional prints then made at Sam's club!)of my son in very inexpensive Christmas ornament picture frame (picked up at Michael's with a coupon.) I also made hot cocoa mix which I put in dollar store tins with the instructions on how to mix the cocoa. I printed the instructions on colored paper with a cute photo of my son & called it "Anthony's Hot Cocoa Mix." To save money on holiday cards, again, took the photo at the Picture People & scanned it on my computer. If you order actual holiday photo cards, they can get expensive if you have to send out 50 or 100 like we do. We used Photoshop to make a 5 X 7 photo card. So, instead of paying for Photo Cards, we paid the lower price for 5 X 7 prints. My sister-in-law did the same thing with 4 x 6 prints.
Finally, if you are getting together, it might just be ok for only kids to get one gift or two gifts a piece to open up. Again with a set price limit or perhaps the parents can just bring a wrapped present & the gifts can be from Santa for them to open. In the meantime, why not focus on just enjoying the time together? Especially since everyone is not from the same area. Surely if the kids have something to open, the adults will be fine not doing gifts or perhaps you & your siblings can go in on one nice gift for your parents as well. Sing carols, make a special meal together or everyone make one thing to share, watch movies, play games, make a real ginger bread house together & have a contest where the winner gets to take it home. It's hard, I know, but hopefully you have gotten some good ideas & your siblings will agree to making some changes.
Good luck to you!