I haven't messed with routers yet, so I could be wrong about this, but based on what I know about them, you can't really specify which apiary they output each drone to, right? What I mean is, if for example you have a router handling two apiaries, one with imperial bees and the other with industrious, if both queens happen to die at the same time, then there's a chance the router might end up breeding the imperial princess with the industrious drone, and the industrious princess with the imperial drone. Unless that's what the diamond pipes are for? If so, can you expand on how this would work?