I believe that Ceres members have to be involved in agriculture in some way ("I eat" doesn't count <g>.)
Have you considered membership in a non-collegiate sorority?
The P.E.O. Sisterhood was founded as a college sorority in 1869 but chose to become a community organization in the early 1870's. (
www.peointernational.org). Other such organizations are Beta Sigma Phi (
www.betasigmaphi.org) and Epsilon Sigma Alpha (
www.esainternational.org). They promote philanthropy and service, and provide opportunities for fellowship too.
I also suggest the American Association of University Women (
www.aauw.org), which promotes eduation and equity for women and girls, and self-development over the lifespan, and positive societal change.