True when the prompt belongs to a multi-participant route.
This boolean flag (bool) belongs to FInteractionRuntimePromptBuildContext under InteractionRuntime|Prompt.
Runtime and UI code should treat this as resolved state from the owning object. Read it to present, branch, or debug behavior without re-authoring the underlying interaction data.
UPROPERTY(BlueprintReadOnly, Category = "InteractionRuntime|Prompt")
bool bHasMultiParticipantSession = false;