expand_less For now, we use a virtual card, but with no content defined from the context.  A *structure rule can make any Cardtype+agent exist for any given Cardtype, and later it may get some plus cards to related the agent to the [[Intentions]], [[Actions]] and other objects of the [[FlowSystems]] relationships.
For now, we can represent collective agency in [[Role]] cards, but maybe we want a user defined type (e.g. [[Circle]]). for this.