I would like that in this thread we explain the differents universities models, i will start speaking about UNED (the spain distance university), althought i think that in all spanish universities is the same.
In UNED someone can study for obtain some certificate (http://www.uned.es/vep/images/organigrama.gif), for obtain a degree "diplomatura" or "licenciatura" (sorry, i am not sure if this words has a direct translation), and this person can study to be a doctor, too (the highest titulation, only who want be professor take this studies).
In the certificates, a class can be in one or various departments. In the other studies, a class only can be in one department.
One department can teach class of one or more faculties.
I think that the diagram about this in dotlrn actually is http://pikachu.innova.uned.es/dev/img/dotlrn_communities-relations.png , because this is the datamodel http://pikachu.innova.uned.es/dev/img/tables-dotlrn.png.
Perhaps, we could implement something similar to http://pikachu.innova.uned.es/dev/img/dotlrn_communities-relations-new.png using acs_rels for the composition relation. Althought is possible than in this thread we change this idea.