This case-sensitive code system http://hl7.org/fhir/goal-relationship-type defines the following codes:
Code
Display
Definition
predecessor
Predecessor
Indicates that the target goal is one which must be met before striving for the current goal.
successor
Successor
Indicates that the target goal is a desired objective once the current goal is met.
replacement
Replacement
Indicates that this goal has been replaced by the target goal.
part-of
Part Of
The relationship.target is a larger goal of which this particular goal is a component or step for.
other
Other
Indicates that the relationship is not covered by one of the pre-defined codes. (An extension may convey more information about the meaning of the relationship.).