Travel Agent

             +----------+  +--------+  +--------+  +--------+
             |  User 1  |  | User 2 |  | User 3 |  | User 4 |
             +----------+  +--------+  +--------+  +--------+
                  |            |          |        / 
                  |            |          |       / 
                  V            V          V      V
             +----------+  +---------+  +---------+
             |  Agent 1 |  | Agent 2 |  | Agent 3 |-------
             +----------+  +---------+  +---------+       \
            /  |  |  \    / | \  \________|_|_|_|______    \
           |   |  |   \__/__|__\__________|_|_|_|_____ \    \
           |  __\__\____/  /    \_____    | | | |     \ \    \
           | /   \  \_____/_________  \   | | | |      | |    \
           | |    \___   /          \  \  | | |  \     | |     \
           | |        \  |           \  | | | |   \    | |      \
           | |    _____|_|____________|_|/ /  |    \___|_|_      \
           | |   /     | |   _________|_|_/   |        | | \      \
           | |  /      | |  /         | |     |        | |  |      \
           | | |       | | |          | |     |        | |  |       |
           V V V       V V V          V V     V        V V  V       V
      +-----------+  +-----------+  +-----------+   +-----------+ +-----------+
      | Cluster A |  | Cluster B |  | Cluster C |   | Cluster D | | Cluster E |
      +-----------+  +-----------+  +-----------+   +-----------+ +-----------+