Non-custodial Parent's Spouse Financial Information?

I'm currently applying financial aid to WashU, and they require both my non-custodial parent and his spouse's information. However, I have never met or even talked to my stepmom before, and she and I have no connection whatsoever. She makes 90k+ a year and has her own daughter, and she will not provide any financial assistance for me in college. Is there any way I can waive her information (house, income, etc) when applying for financial aid? Or do I have to wait until I get my financial aid package to do so? Because as of now, my parents and stepparents' income combined from both of my parents and stepparents is well over 200k. However, without my stepmom, it drops drastically. My custodial parent and her spouse (mom and stepdad) only make 40k a year combined. Thus, I really need financial assistance.