How can I send messages from user A to user B on the blockchain network? A diagram has been mentioned below:
If I have a blockchain network with 5 nodes. Each node represents one "Organisation". How can User A in Organisation 1 send a message to exact User B in organisation B? Can send messages between two blockchain nodes, for example node 1 and node 3 or other node in the blockchain network. But, at User A, how can he determine "where is User B" ?