I think it is grabby for joint parties to expect two gifts.
the costs of a party (even shared) are much more expensive than the amount the kids receive in gifts so if you really must play the game of comparing costs, think about it properly
Why should they contribute twice as much for a party the parents paid half the cost for?
My twins had very few joint parties, they did a weekend each different themes, different venues, they had a joint family dinner on their actual birthday.
I didn’t want them to feel they had to have joint things, that includes gifts, presents, friends, cake, etc
The twin Mum who said “two gifts” just why? Do they really sit there and count up who gave what to who?
Wouldn’t bother me if no one gave gifts.