My brother's getting married in a few months and his soon-to-be mother-in-law has invited us to combine bridal showers with her. In reviewing the guest list, she has 2.5 times as many invitees as we do. How should we split expenses? Our thought was to pay for our guests and she pay for hers as she's not willing to reduce the number of invitees. Is this appropriate?
I wouldn't do this, as it is inappropriate for her to host. Plus, it sounds like she is inviting too many guests, which is a prime example of why we have this silly little rule about mothers not hosting--they typically try to garner as many gifts as possible.
It is best to host your own shower and abide by proper shower etiquette (we have many posts concerning this). This is very important, especially if this is a traditional gift giving event. It shouldn't appear to be a giant gift grab.
I really couldn't advise you on your original question as it is improper to host a large shower and for the mother to host.