RemoteActor
RemoteActivity

Collab

CollabFulfillsInvite
    collab CollabId

    UniqueCollabFulfillsInvite collab

CollabInviterRemote
    collab CollabId
    collabNew CollabFulfillsInviteId
    actor  RemoteActorId
    invite RemoteActivityId

    UniqueCollabInviterRemote       collab
    UniqueCollabInviterRemoteInvite invite