BPMN21 — Correlation across conversations

The metamodel seems to be missing relations between the correlation
information in multiple conversations of the same collaboration /
choreography. For example, in Figure 11.3 (Conversation diagram
depicting several conversations between Participants in a related
domain) how does the process internal to Consignee handling the
Consignee-Retailer conversation map its correlation information to the
correlation info in the Consignee-Supplier conversation? Without this
the Consignee conversations with the Retailer and Supplier will be
uncoordinated.