ryan, i am as well a little confused about your terminology. is your implementation user-based or role-based? what is an "instruction"?
Are you able to express what you did in the terminology of RBAC? Here is a good introduction of RBAC: http://csrc.nist.gov/rbac/rbacSTD-ACM.pdf
You might check as well we did on implementing RBAC in: http://wi.wu-wien.ac.at/home/mark/publications/ccs01.pdf
