The following design decisions must be made for relationships: navigation, containment, refinement, and multiplicity implementation.
Associations and aggregations are bidirectional relationships. During design, associations are revisited to determine if bidirectionality is indeed needed. If possible, the relationship is made unidirectional (i.e., navigable in only one direction) since unidirectional relationships are easier to implement and maintain.
SETTING NAVIGATION IN RATIONAL ROSE
Right-click at the end of the association or aggregation line to be made non-navigable to make the shortcut menu visible. ...