One of our guests (FH's brother's best friend) texted FH to ask if he could bring his girlfriend and his brother to the end of our reception. That way we don't need to provide a seat or a meal for them, and they could just come to party. FH and I both agree that it's not appropriate, but can't figure out a way to word the response in a tactful and polite manner. I mean, we're celebrating our marriage, it's not just some party where you show up to and drink and dance the night away. All the responses I've formulated are a little too abrasive, and I'm sure FH doesn't want me ruining a relationship with someone he'll have to continue to see in years to come.
I know some of you out there are great at phrasing these messages so they're firm and get the point across but still gentle enough. Help, please!