https://npc.collegeboard.org/app/rice is Rice’s net price calculator, using the College Board template. It does ask if your parents are divorced. You need to put in the income and assets for both of your parents into it. If you are not sure how to fill it in, contact Rice’s FA department for instructions.
http://talk.collegeconfidential.com/financial-aid-scholarships/2083835-faq-divorced-parents-financial-aid-and-net-price-calculators.html has more general information on the divorced parent situation.