CollabFulfillsJoin
    collab CollabId

    UniqueCollabFulfillsJoin collab

CollabApproverLocal
    collab CollabFulfillsJoinId
    accept OutboxItemId

    UniqueCollabApproverLocal       collab
    UniqueCollabApproverLocalAccept accept

CollabApproverRemote
    collab CollabFulfillsJoinId
    actor  RemoteActorId
    accept RemoteActivityId

    UniqueCollabApproverRemote       collab
    UniqueCollabApproverRemoteAccept accept

CollabRecipLocalJoin
    collab   CollabRecipLocalId
    fulfills CollabFulfillsJoinId
    join     OutboxItemId

    UniqueCollabRecipLocalJoinCollab   collab
    UniqueCollabRecipLocalJoinFulfills fulfills
    UniqueCollabRecipLocalJoinJoin     join

CollabRecipRemoteJoin
    collab   CollabRecipRemoteId
    fulfills CollabFulfillsJoinId
    join     RemoteActivityId

    UniqueCollabRecipRemoteJoinCollab   collab
    UniqueCollabRecipRemoteJoinFulfills fulfills
    UniqueCollabRecipRemoteJoinJoin     join