EJB bi-directional, one-to-many relationships

Is it possible to create bi-directional relationships between CMPs in Netweaver? When creating a one-to-many relationship there seems to be no way to specify a CMR field at both ends of the relationship, although when viewing the created relationships in persistence.xml editor there is a read-only data entry field called 'Cmr field' with the value 'not specified' at the other end of the relationship, implying that bidirectional relationships are possible.

Do I need to use a many-to-many type relationship to use bi-directional relationships?