Hello all!
This is my first message here, I hope i will get lucky

There is a ER model on a posted picture, and i have a problem with the last aggregation PrijavaPolaganja. Sorry for foreign language, but I have drawn this in Visio and lost the document

Kurs=Course; Profil=Profile; Program=Program

; Nastavnik=Teacher; Polaznik=Student; Angazovanje=CourseListForTeacher; IzborKurseva=CourseListForStudent;
PrijavaPolaganja is when student wants to pass the exam on particular Course that is on his lsit, and being tested by a Teacher that is on that Course.
In Program we have CourseID and ProfileID as key, and those "fields" are part of keys of two underlying aggregations (TeacherID,CourseID,ProfileID & StudentID,CourseID,ProfileID).
Is there any way that I can make the last aggregation possible to reflect those real life constraints? Student can pick a Course from his list and get tested by a Teacher that is on that Course in that particular Profile?