Birthday party guest dilemma?

First of all, My daughter will be 3 next month. Her party is in 2 weeks. My mother in law refuses to come to the birthday party that we are throwing for our daughter at my mom's house, though she would only have to drive an hour compared to our 2 day drive. The past 2 years she has thrown her a separate party at her house. Last year she didn't have anyone else there but us. This year she invited all her snooty friends and their grandkids and great grandkids. The problem is, most of the kids she invited are much older than my daughter (all boys between 7 and 9), and I'm worried that the older kids are going to play too rough and she's going to get hurt. How can I politely tell her that even though it's her house I don't feel comfortable with her having them around my daughter? Do parents have say in stuff like this when they are at someone else's house?