We are getting married next spring in the midwest, where I am originally from. My fiance's entire family/group of family friends is from the east coast and we anticipate about a third of those invited from the east coast will be unable to make the trip. We expected this and opted to have our engagement party, which my fiance and I financed, at his parents' home in an effort to celebrate with those who we thought might be unable to attend.
Now his grandmother is essentially demanding that we have an after-wedding party on the east coast for those who couldn't make it to the wedding. While I'm sad that the location of the wedding will preclude some people from coming, I don't really want another party after the wedding. She has yet to indicate that she will pay for the party or plan it, so I am assuming (until told otherwise) that it will be up to us to make it happen. What's more, she wants the party to be the weekend after the wedding (we are not taking our honeymoon for a few months).
Although I think it's entirely unnecessary, I am willing to have another party as long as I don't have to contribute financially or do any planning. If she brings it up again, how do I say this without sounding like I am demanding a party?
ETA: grammar corrections