One or several heads connected to the same stem lead to the creation of one chord.
But what about whole heads (since for them there is no such stem)?

Current approach is to join together whole heads that are physically connected. This is not satifactory, as one can see in the following case:

On the left-hand side we have 1 chord with 3 black heads.
On the right-hand side, Audiveris sees 2 chords, one for the 2 upper whole heads and one for the lower whole head.
During the CURVES step, ties are recognized and Audiveris (wrongly) detects an anomaly: the chord on the left-hand side is tied to two different chords on the right-hand size. Consequently, it tries to split the left-hand chord into 2 subchords...

Such behavior was triggered by the fact that the whole heads were wrongly assigned to 2 different chords.

The real question is thus: what would be a correct strategy to correctly assign whole heads into proper chords? Please help me.