So... you have multiple advertising routes, and each box has 5 public addresses, and the complaint is that the boxes can't magically decide how to handle all of the different routes?

When it comes to routing, you have two options, delegate or self-manage. In the case of self-management, yes, if you want complex route management, then you'll need software that handles complex route management.

Why not use Stateless DHCP, and configure a machine with short leases that can update the others as needed? It can handle the complex routing, and the clients just have to frequently ask if there are updates.