It's possible that i didn't explain very good.
How to model a n:m relation between classes and departments?. It looks like acs_rels is the way to do it. But i'm starting with openacs and i don't find specific documentation about use acs_rels. I've read https://openacs.org/doc/openacs-4-6-3/object-system-design.html and https://openacs.org/doc/openacs-4-6-3/permissions-tediously-explained.html and i understand the philosophy, but i would like see simple examples about use acs_rels.
Thanks.