separate logical systems or just independent datasets and perspectives?
If exchanges happen between agents in different systems, then a resource transfer needs to be separated into a Give event (might be called a Shipment) in one system and a Take event (might be called a Receipt) in the other system.
If the agents operate in the same logical system, then a resource transfer can just be a transfer - a single event where the resource moves from the Giver to the Taker - although the Giver and the Taker will have different views of the same event.
Since we all operate in present time as part of ecosystem of planet Earth, one can consider everything as single logical system. On the other side, since we use decentralized information system possibly even full P2P, we should anticipate for that in modeling. In other words, each exchange or event with multiple peers (Agents) involved, will have multiple sources of 'truth' all possibly expressing same event from different perspective (eg. Give/Take, Lend/Borrow etc.).
See also