It is really a very sad state of affairs. The first one who gets engaged gets all the excitement and everyone is jumping out of their skin to do “everything” for her. By the time the last girl in the group gets engaged the rest of the chaburah have moved away, have a bunch of kids, haven’t spoken to the Kallah in years and so forth. It really isn’t fair or nice.
Maybe what you should do is make a bank account with two girls as secretary and treasurer and collect the same amount of money for the entire group, basically enough to cover ALL the girls if you were all getting married at the same time. And do this BEFORE anyone gets engaged. You all decide how much money each is putting into the account, you each choose who would be the one in charge of their parties and you each get to write up a wish list within the budget. The girl in charge of the first Kallah’s party can only spend the agreed upon amount and has to stick to the wish list. If the newlyweds move away, you can choose new “officers” and change the signatory at the bank. But the money will always be available at the bank when the next girl gets engaged. Even when the last girl gets engaged her kallah fund will still be there and available for her wish list.
New friends can buy things on their own or join the system to keep it going, but no one will feel used for having spent a fortune on other girls and not have anything to show for it when it is their turn. What do you think about that?