Should there be a better way to decide who hosts a 10k, 20k, etc. milestone celebration?

Last year, I noticed a Jelly reached a 10k milestone, and no one gave a party for them a full 2 days after the achievement. I don’t want anyone to feel ignored here, so if I see someone has hit the milestone, I will wait a bit, then throw the party myself, but I know the party may mean more if it was from a specific jelly of their liking.
I have thrown 3 parties this weekend, and I am fine with that, but I wonder if others are hesitant to do this. I wish there was some other way to get the party started. Anyone have any suggestions?