Cross-Dressers Cross-Dressers HELPFUL LINKS Tri-Ess. An international organization. Tri-Ess is an educational, social and support group for heterosexual cross-dressers, their partners, the spouses of married cross-dressers and their families. Sigma Epsilon. Learn more about this Atlanta-based chapter of Tri-Ess. Its members include cross-dressers and their significant others from throughout the Southeastern States.