Section 2.1.3 describes the use of .derivedFrom and .hasMember to create bi-directional linkages between parent and child question. The general Observation guidance indicated doesn't really cover creating bi-directional linkages. Is this a typical arrangement? I feel like the general best practice is to have only a one-way linkage (for example DiagnosticReport points to Observations via .results, but Observation doesn't point back to the DiagnosticReport). At best, the linkages will agree (that is the parent points to a child and that child points to the same parent), at worst they will conflict (a parent points to a child but the child points to a different parent). Please confirm that a bi-directional linkage is desirable.