ERD with a table with strange keys

As I said previously I have to do things as my lecturers want until June 8th so Advanced Databases, creating a model for international crowdfunding..

I have the following three tables:

Project ----------- projectID <<Primary Key>> title catagory <<Foreign Key>>

customer -------------- personID <<Primary Key>> forename country <<Foreign Key>>

restrictions --------------- country <<composite Primary Key>> category <<Composite Primary Key>> ageRestricted genderRestricted

My lecturer is saying that the composite primary key must be accessible without needing reference to two tables..

In ERD/UML is there anything wrong with having a look up table referenced from two other tables?

Thanks for any pointers google has let me down as has the databases groups on facebook...

Adam.